This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2007-227234, filed Sep. 3, 2007, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to an electronic apparatus having a graph display function of plotting a graph of an input mathematical expression on a display unit.
2. Description of the Related Art
Conventionally, a small-sized electronic calculator called “graphing calculator” has been widely put to practical use. According to the graphing calculator, user selects a graph type (coordinate system such as orthogonal coordinate system or polar coordinate system) and inputs various mathematical expressions in accordance with a predetermined format given corresponding to the selected graph type. The graphing calculator plots and displays a graph of an input mathematical expression. The graphing calculator is used in a field of education, and such learning is made that user inputs various expressions and the graphs are plotted, then the user confirms the graphs.
As disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2003-296285, use of the graphing calculator allows effective learning as below. That is, a student inputs an expression element including a variable “X” or “θ”, for example, to a corresponding field “□” in the predetermined format of “Y=□” (orthogonal coordinate system) or “r=□” polar coordinate system), then a graph corresponding to the input is plotted.
Although the graphing calculator can plot and display graphs of various input expressions, the notation of expressions to be input is limited to “Y −□” in the orthogonal coordinate system or limited to “r−□” in the polar coordinate system. In addition, the notation of corresponding variables to be input is also predetermined as “X” or “θ”.
Thus, for example, in order to plot a graph indicative of relationship between P and T in the equation of state “PV=nRT” in the orthogonal coordinate system, the user is required to perform a troublesome procedure of changing the form of the equation from “PV=nRT” to “Y=(nR/V)·X” by transforming “PV=nRT” to “P=nRT/V” and substituting Y for P and X for T. Besides, such setting of coordinates that elements of an expression, i.e., two or more variables, are gathered together and regarded as one parameter in graph display is not possible.
According to one embodiment of the present invention, an electronic apparatus having a graph display function comprises an expression memory configured to store an expression including expression elements, a parameter setting unit configured to set an expression element included in the expression stored in the expression memory as a coordinate parameter in accordance with operation made by a user and a graph plotting unit configured to plot a graph of the expression based on the coordinate parameter set by the parameter setting unit.
According to another embodiment of the present invention, a graph plotting method executed in an electronic apparatus having a graph display function, the graph plotting method comprises inputting an expression including expression elements, setting an expression element included in the expression as a coordinate parameter in accordance with operation made by a user and plotting a graph of the expression based on the set coordinate parameter.
According to another embodiment of the present invention, a calculator includes a key input unit, a display unit, a controller and a memory, the controller executes inputting an expression including expression elements using the key input unit, setting an expression element included in the expression as a coordinate parameter in accordance with operation made by a user, and plotting a graph of the expression based on the set coordinate parameter.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present invention and, together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the present invention in which:
An embodiment of an electronic apparatus having a graph display function according to the present invention will now be described with reference to the accompanying drawings.
The control unit (CPU) 11 boots up a system program prestored in a memory area 12 such as a flash ROM in response to input data that is input from an input unit 14 and controls operations of respective circuit components by using a working area 13 such as a RAM.
The input unit 14, memory area (ROM) 12 and working area (RAM) 13 are connected to the controls unit 11. In addition, a display unit 15 is connected to the control unit 11. On the display unit 15, a character and expression display area 15a and a graph display area 15b are set as needed.
The memory area 12 prestores the system program for controlling overall processing of the electronic circuit of the graphing calculator 10. In addition, the memory area 12 stores various execution programs 12a, character-coordinate relation information 12b, and formula-coordinate relation information 12c. The execution programs 12a include programs for executing various operations. The character-coordinate relation information 12b stores characters and corresponding coordinate systems. The formula-coordinate relation information 12c stores various formulas such as a mathematical formula or a physical law in association with a coordinate system, a coordinate parameter and a plotting range.
The input unit 14 is provided with a key input unit including a menu key 14a, an option key 14b, character and numeral keys 14c, a cursor key 14d, and an execution (EXE) key 14e.
The menu key 14a is operated for selecting any mode from various operation modes of the graphing calculator 10, for example, “calculation mode” or “graph mode”.
The option key 14b is operated, in the case where any of the operation modes is being executed in the graphing calculator 10, to display a menu screen for prompting a user to select a function specific to the present operation mode. For example, when the option key 14b is operated during the execution of the “graph mode”, selectable functions including “graph type automatic setting”, “coordinate parameter automatic setting” and “formula call instruction” are displayed on list.
The character and numeral keys 14c include keys for inputting symbol, character or numeral (hereinafter, generically referred to as “expression element”). The user inputs desired expression by operating a combination of some of the character and numeral keys 14c. The cursor key 14d is operated for moving a cursor pointer P, which is displayed on the display screen of the display unit 15, in a desired direction. The execution key 14e is operated to finalize an immediately preceding operation and to advance the process to the next procedure, for example.
Form of the keys 14a to 14e, which are provided as the key input unit, are not limited to key form. The keys may be configured as displayed keys; namely, display screen of the display unit 15 may be a touch screen and indicators of the keys may be displayed on the touch screen. When any of the displayed keys is touched, operation information is input in accordance with the touch.
The working area (RAM) 13 includes an initial setting memory area 13a which prestores initial setting information set in accordance with operation made by the user. The initial setting memory area 13a prestores information such as data indicating a graph type, e.g., orthogonal coordinate data, and range data indicating a display range. In addition, the working area 13 includes an expression memory area 13b and a temporary memory area 13c. The expression memory area 13b stores an expression including a symbol, character, numeral, etc., which are input by the character and numeral keys 14c in the graph mode. The temporary memory area 13c temporarily stores various data used in operations.
Next, the operation of the graphing calculator 10 having the above-described configuration is described.
Firstly, when the user turns on the power of the graphing calculator 10 and operates the menu key 14a, various selectable operation modes such as a calculation mode and a graph mode are displayed. When the user selects the graph mode by using the cursor key 14d, the graphing calculator 10 is set in the graph mode.
When the formula call instruction is not input and an expression is input (No in step A1), the input expression is stored in the temporary memory area 13c and displayed on the display unit 15 (step A2). A cursor pointer P is displayed at the end of the expression. A character and numeral input standby state is maintained until the execution (EXE) key 14e is operated (step A3). When the execution key 14e is operated (Yes in step A3), the input expression is finalized. Then, it is determined whether or not the input expression includes an equal sign (step A4). When the input expression includes an equal sign (Yes in step A4), the flow goes to step A5. On the other hand, when the input expression does not include an equal sign (No in step A4), “y=” is attached to the left end of the expression (step A6). Then, the expression is defined as the object of graph plotting and stored in the expression memory area 13b (step A5). Then, the expression is displayed on the display unit 15 without the cursor pointer P (step A7).
On the other hand, when the formula call instruction is input in step A1 (Yes in step A1), formulas are read out from the formula-coordinate relation information 12c (
After the object of the graph plotting is defined as described above, the flow goes to the coordinate system setting process shown in
When the execution key 14e is operated (Yes in step B1), a graph type stored in the initial setting memory area 13a is read out and set (step B8). The user may set in advance a graph type (coordinate system) by default. This default graph type is read and set as a coordinate system for graph plotting. The set coordinate system for graph plotting is stored in the temporary memory area 13c.
When the execution key 14e is not operated (No in step B1), it is determined whether or not the option key 14b is operated (step B2). When the option key is operated (Yes in step B2), a selection menu is displayed on the display unit 15 (step B3). On the selection menu screen, selectable functions specific to the graph mode are displayed. For example, on the display screen, items of “graph type” and “graph type automatic setting” are displayed prompting the user to select whether the graph type will be set by the user or set automatically.
When the user selects the item of “graph type” in step B4, a list of selectable coordinate systems is displayed and the user selects one of the coordinate systems (step B5). The selected coordinate system is set as the coordinate system for graph plotting. The coordinate system for graph plotting is stored in the temporary memory area 13c.
On the other hand, when the user selects the item of “graph type automatic setting” in step B4, a coordinate system is determined based on data stored in the memory area 12 (step B6). When the object of graph plotting defined in the expression input process (see
Then, it is determined whether or not the execution key 14e is operated (step B7). When the execution key 14e is operated (Yes in step B7), the coordinate system determined in step B6 is settled. When the determined coordinate system is not a coordinate system which the user desires, the user does not operate the execution key 14e (No in step B7) and the graph type can be reconfigured (step B5).
After the coordinate system for graph plotting is determined, the flow goes to the coordinate parameter setting process shown in
When the automatic setting instruction is not made (No in step C2), the user inputs characters in the fields by operating the character and numeral keys 14c and input characters are set as the coordinate parameters for graph plotting (step C3). The set coordinate parameters are stored in the temporary memory area 13c.
For example, in the case where “Y” is input to the field of “ordinate axis” and “X” is input to the field of “abscissa axis” in the orthogonal coordinate system, “Y” is used as the ordinate axis and “X” is used as the abscissa axis when plotting a graph.
On the other hand, when “coordinate parameter automatic setting” is selected in step C2 (Yes in step C2), coordinate parameters are automatically set (step C4). Coordinate parameter automatic setting process executed in step C4 is described in detail in
After the coordinate parameters are set, the flow advances to the graph display process shown in
When the object of the graph plotting does not include any unknown constant (No in step D1), the flow goes to step D2.
On the other hand, when it is determined that the object of the graph plotting includes an unknown constant (Yes in step D1), a screen requiring the user to input a numerical value corresponding to the unknown constant is displayed (for example, shown in
Then, a graph of the object of graph plotting is plotted and displayed (step D2). The graph is plotted in the coordinate system for graph plotting determined in the coordinate system setting process shown in
The range of graph plotting corresponds to setting of plotting range data (range data), which is stored in advance in the initial setting memory area 13a.
Hereinafter, operation examples according to the graph mode will he described.
In the expression input process (see
When the execution key 14e is operated by the user (Yes in step A3), it is determined whether or not the input expression includes an equal sign (step A4). In this example, the input mathematical expression includes the equal sign (Yes in step A4), and the input expression “100=RI” is defined as the object of graph plotting and stored in the expression memory area 13b (step A5). The expression defined as the object of graph plotting is displayed on the display unit 15 (step A7).
In the coordinate system setting process (see
In the coordinate parameter setting process (see
In the graph display process (see
The first operation example demonstrates a case in which simply the user inputs an express-on, and sets a graph type and coordinate parameters without transforming the expression or substituting characters. In such a case, the graphing calculator 10 can plot a graph corresponding to the input expression.
In the expression input process (see
In the coordinate system setting process (see
In the coordinate parameter setting process (see
In the graph display process (see
The expression data is read from the expression memory area 13b, and coordinate system data and coordinate parameters are read from the temporary memory area 13c. Then, a graph of the expression “Y=A(X−T)+B” is plotted and displayed (step D2). As shown in
In the expression input process (see
In the coordinate system setting process (see
In this operation example, the input expression “r=2(1+cosθ) ” includes the characters “r” and “θ”. Therefore, data indicative of the polar coordinate system is obtained in correspondence with the characters from the character-coordinate relation information 12b (
In the coordinate parameter setting process (see
The third operation example demonstrates that the user inputs an arbitrary expression and configures a graph type (coordinate system) to be automatically set, whereby the coordinate system can automatically be set on the basis of characters which the expression of the object of graph plotting stored in the expression memory area 13b includes.
In the expression input process (see
When the user operates the execution key 14e (Yes in step A3), it is determined that the input expression includes an equal sign (Yes in step A4). The input expression is defined as the object of graph plotting and stored in the expression memory area 13b (step A5). The expression is displayed on the display unit 15 (step A7). Then, the expression input process is completed.
In the coordinate system setting process (see FIG. 6)), when the user operates the execution key 14e (Yes in step B1), initial setting of a graph type which is stored in the initial setting memory area 13a is read and set (step B8). In the present example, the orthogonal coordinate system is stored by default and the orthogonal coordinate system is read and defined as the graph type for graph plotting. Then, the flow goes to the coordinate parameter setting process.
In the coordinate parameter setting process (see
To automatically set coordinate parameters, the user is required to operate the option key 14b on the parameter setting screen and to select the item of “coordinate parameter automatic setting”. When the user operates the option key 14b and “coordinate parameter automatic setting” is selected (Yes in step C2), the coordinate parameter automatic setting process shown in
Firstly, it is determined whether or not the left side of the expression which is the object of graph plotting and stored in the expression memory area 13b includes any character (step T1). When it is determined that the left side of the expression does not include any character (No in step T1), a coordinate parameter is not set (step T2) and the flow advances to step T6. On the other hand, when it is determined that the left side of the expression includes any character (Yes in step T1), then it is determined whether or not the left side includes only one character (step T3). When it is determined that the left side includes only one character (Yes in step T3), this one character is set as a coordinate parameter for graph plotting (step T4), and the flow advances to step T6. When it is determined that the left side of the expression includes a plurality of characters (No in step T3), the last character in the left side of the expression is set as a coordinate parameter for graph plotting (step T5), and the flow advances to step T6.
A similar processing to the processing executed with respect to the left side of the expression in steps T1 to T5 is executed with respect to the right side of the expression in steps T6 to T11. The coordinate parameters set through the processing of steps T1 to T10 are displayed (step T11). The set coordinate parameters are stored in the temporary memory area 13c and the coordinate parameter automatic setting process is terminated.
In the present operation example, since the left side of the expression stored in the expression memory area 13b is “A”, it is determined that the left side includes a character (Yes in steps T1 and T3). Accordingly, “A” is set as a coordinate parameter for graph plotting. Similarly, since the right side of the expression stored in the expression memory area 13b is “BC2”, it is determined that the right side includes more than one character (Yes in step T6 and No in step T8). Therefore, the last character in the right side, i.e., “C” is set as a coordinate parameter for graph plotting (step T10). As shown in
To settle the coordinate parameters for graph plotting which are automatically set as described above, the user operates the execution key 14e (Yes in step C5).
The graph display process is similar to that in the above described operation examples, so a description thereof is omitted.
As described above, the fourth operation example demonstrates that coordinate parameters can be automatically set. That is, when automatically setting of coordinate parameters for graph plotting corresponding to the set coordinate system (graph type) is configured, the coordinate parameters for graph plotting are automatically set based on the numbers and positions of characters included in the left side and right side of the expression which is the object of graph plotting and stored in the expression memory area 13b.
In the expression input process (
Subsequently, the coordinate system setting process (see
In the coordinate parameter setting process (see
As described above, the fifth operation example demonstrates that, in the case where the user calls a list of formulas and selects an arbitrary formula, the user can configure a coordinate system or coordinate parameters corresponding to the selected formula to be automatically set. In response to operation made by the user, a coordinate system and coordinate parameters corresponding to the selected formula are automatically set, and a graph of the selected formula is displayed.
Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
Number | Date | Country | Kind |
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2007-227234 | Sep 2007 | JP | national |