Sample 3 Array and Table




PdependsOnH()

FUNCTION PdependsOnH()
    SYSTEM(BackGround=995, FontSize=16)
    DO height = 250, 10000, 250      ! height from 250m to 10000m in 250m steps
        idx = height/250
        $HeiPres(idx, 1) = height
        $HeiPres(idx, 2) = BarometricPressure(height)
    ENDDO
    F2()
    F3()
    F4()
END

FUNCTION BarometricPressure(h)
    a = 0.0065    ! K/m
    T0 = 15 + 273 ! K
    M = 0.02896   ! kg/mol
    g = 9.81      ! m/s2
    R = 8.314     ! J/K/mol = kg*m/s2 /K/mol
    P0 = 1013     ! hPa = h N/m2 = h m*kg/s2 /m2
    BarometricPressure = P0 * ((1 - a*h/T0) ^ (M*g/R/a))
END

FUNCTION F2() ! standard loop graph demonstrates single step plotting
    DLG(R=2,C=4,BackG=99, AXis=3, X=1,MAX=8000,TIt='1 LINE call / data point', Y=1,MIN=300,MAX=1000,TI='pressure/hPa')
    DO height = 250, 8000, 250
        pressure = BarometricPressure(height)
        LINE(AX=3, X=height, Y=pressure, Symbol='○', Width=3, Draw=-900)
    ENDDO
END

FUNCTION F3() ! internal $ loop variable, depends on matrix $HeiPres(height, pressure)
    DLG(R=2,C=4,BackG=990, AXis=4, X=1,MAX=8000,TIt='1 call for full matrix',   Y=1,TI='pressure/hPa',MIN=300,MAX=1000)
    LINE(AX=4, Col=1,XVec=$HeiPres,  Col=2,YVec=$HeiPres, Symbol='○', Draw=-9)
END

FUNCTION F4() ! show p(h) array and explain
    DLG(R=2,C=4, Nr=8, TItle='height and pressure', Array=$HeiPres, Ti='nr,height/m,pressure/hPa')
    DLG(B='OK, show script', B='Quit HicEst', XEQ='SYSTEM(QUIT=1)', E='#Explain')

#Explain We calculate the atmospheric pressure as a function of altitude You need to know: . Line 1 is always executed at start. . A FUNCTION call auto-runs the script. . This script starts with FUNCTION PdependsOnH() . To see the code: hit ESCAPE . All 4 windows are modeless: code does not wait for closure . NR=.. or AX=.. assign the numbers for modeless windows A matrix $HeiPres with 81 rows and 2 columns is built . A matrix column can be either numeric or text Functions return a value with the RETURN ... statement Useful to know: . Rows=r and Cols=c divide the screen in r*c areas . Nr=wdwNr or AX=axNr will be within this screen area. . Press F1 over an item to show its value. . Vectors and matrices are edited with the DLG function. . Define FUNCTIONs should be at the end of the code.


    IF($txtRC=='OK, show script')
        DLG(Kill=3, Kill=4, Kill=8)
    ELSEIF($txtRC == "Quit HicEst")
        SYSTEM(Quit=1)
END
ENDIF
END

#Explain
We calculate the atmospheric pressure as a function of altitude

You need to know:
.	Line 1 is always executed at start.
.		A FUNCTION call auto-runs the script.
.		This script starts with FUNCTION PdependsOnH()

.	To see the code: hit ESCAPE

.	All 4 windows are modeless: code does not wait for closure
.	NR=.. or AX=.. assign the numbers for modeless windows

A matrix $HeiPres with 81 rows and 2 columns is built
.	A matrix column can be either numeric or text

Functions return a value with the RETURN ... statement

Useful to know:
.	Rows=r and Cols=c divide the screen in r*c areas
.		Nr=wdwNr or AX=axNr will be within this screen area.
.	Press F1 over an item to show its value.
.	Vectors and matrices are edited with the DLG function.
.	Define FUNCTIONs should be at the end of the code.
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