Gillee

How to generate a ColumnGraph with bars ...

Asked: Gillee 232 Product: Maple 2024

April 01 2024

2 2

Hello,

I would like to generate a ColumnGraph such that the bars are centered over 1, 2, and 3. For example, I have a vector:

x:= Vector([1,2,3]);

When you execute ColumnGraph(x), you a get the first bar centered over 0.375, instead of 1, second bar centered over 1.375, instead of 2, and so on.

Thanks for your help.

singularvalues and eigenvectors...

Asked: Gillee 232 Product: Maple 2023

March 12 2024

1 0

WHY DOES THE TRANSPOSE OF Vt DETERMINED BY THE FUNCTION SingularValues NOT AGREE WITH THE evectors CALCULATED BY THE FUNCTION Eigenvectors?

>	restart: with(LinearAlgebra):

>	X := Matrix([[8.79,9.93,9.83,5.45,3.16], [6.11,6.91,5.04,-0.27,7.98], [-9.15,-7.93,4.86,4.85,3.01], [9.57,1.64,8.83,0.74,5.80], [-3.49,4.02,9.80,10.00,4.27], [9.84,0.15,-8.99,-6.02,-5.31]], datatype=float[8],order=Fortran_order);

(1)

>	U,S,Vt:= SingularValues(X, output = ['U', 'S', 'Vt'],thin=true)

(2)

>	SDM:= DiagonalMatrix(S[1..5],5,5)

(3)

THIS EQUALS TO ORIGINAL X MATRIX

>

U.SDM.Vt

(4)

>	X -~ U.SDM.Vt

(5)

EIGENVALUES

>

S*~S

Vector(6, {(1) = 754.5312606638714, (2) = 512.7138273868854, (3) = 73.24600906942915, (4) = 35.82888224512065, (5) = 4.059820634692874, (6) = 0.})

(6)

EIGENVECTORS

>	Transpose(Vt)

(7)

COMPARE LINE (6) AND THE evalues OF LINE (8), IN AGREEMENT.

COMPARE LINE (7) AND THE evectors OF LINE (8), NOT IN AGREEMENT.

>	evalues, evectors:= Eigenvectors(Transpose(X).X)

(8)

>	sdm:= DiagonalMatrix(evalues[1..5],5,5)

(9)

THIS SHOULD EQUAL TO THE ORIGINAL X MATRIX??

>	U.sdm.Transpose(evectors)

(10)

>	X -~ U.sdm.Transpose(evectors)

(11)

>

Download SVD_test.mw

How can I use a compiled Fortran code in...

Asked: Gillee 232 Product: Maple

January 30 2024

1 1

I have entered a few examples from the Maple Example Worksheets on the the topic of using compiled Fortran code. I got two simple examples to work as shown in my worksheet below. The third example was to perform a matrix multiplication and that is where I get the "Error, (in fmat_mult) unhandled return type". Could you point out my mistake? Thank you in advance.

Using compiled FORTRAN code:

1) write a FORTRAN function in Geany

2) compile it to an object file *.o

2) open terminal in the folder where the file is saved

3) generate a *.dll file by: gfortran -shared -o mult.dll mult.o

4) setup the call to your functions: see lines fmult:= define_external( ) and fmultf:= define_external( ).

>	restart: kernelopts(version);

(1)

Multiply two integers

>	fmult:=define_external('mult', LIB= "C:/Users/familee/OneDrive/Documents/Maple/DLL-example/mult.dll", FORTRAN, 'a'::(integer[4]), 'b'::(integer[4]), RETURN::(integer[4]))

(2)

Multiply two floating point numbers

>	fmultf:=define_external('multf', LIB= "C:/Users/familee/OneDrive/Documents/Maple/DLL-example/multf.dll", FORTRAN, 'a'::(float[8]), 'b'::(float[8]), RETURN::(float[8]))

>	fmult(10,3)

(3)

>	fmultf(10.1,3.3)

(4)

>	fmultf(100.234,67.901)

(5)

Matrix multiplication example

>	a:=Matrix([[1.,4.,7.],[2.,5.,8.],[3.,6.,9.]],datatype=float[8],order=Fortran_order);

Matrix(3, 3, {(1, 1) = 1.0, (1, 2) = 4.0, (1, 3) = 7.0, (2, 1) = 2.0, (2, 2) = 5.0, (2, 3) = 8.0, (3, 1) = 3.0, (3, 2) = 6.0, (3, 3) = 9.0})

(6)

>	b:=Matrix([[1.,4.,7.],[2.,5.,8.],[3.,6.,9.]],datatype=float[8],order=Fortran_order);

Matrix(3, 3, {(1, 1) = 1.0, (1, 2) = 4.0, (1, 3) = 7.0, (2, 1) = 2.0, (2, 2) = 5.0, (2, 3) = 8.0, (3, 1) = 3.0, (3, 2) = 6.0, (3, 3) = 9.0})

(7)

>	c:=Matrix(1 .. 3, 1 .. 3, fill = 0.,datatype=float[8],order=Fortran_order);

Matrix(3, 3, {(1, 1) = 0., (1, 2) = 0., (1, 3) = 0., (2, 1) = 0., (2, 2) = 0., (2, 3) = 0., (3, 1) = 0., (3, 2) = 0., (3, 3) = 0.})

(8)

>

a.b

Matrix(3, 3, {(1, 1) = 30.0, (1, 2) = 66.0, (1, 3) = 102.0, (2, 1) = 36.0, (2, 2) = 81.0, (2, 3) = 126.0, (3, 1) = 42.0, (3, 2) = 96.0, (3, 3) = 150.0})

(9)

Is it possible to use a subroutine to pass a matrix?

mat_mult,f subroutine returns c = a.b

FORTRAN code for mat_mult.f

       SUBROUTINE mat_mult(a,b,c,m,n)
C
C      Compute matrix multiplication.
C
       INTEGER i,j,k
       INTEGER m,n

       REAL*8 tmp
C      m rows by n cols
       REAL*8 a(m,n)
       REAL*8 b(m,n)
       REAL*8, intent (out)::c(m,n)
C      m = n
       DO 11 j=1,n
         DO 12 i=1,n
            tmp = 0.0
            DO 13 k=1,n
               tmp = tmp + a(i,k) * b(k,j)
13         CONTINUE
            c(i,j) = tmp
12      CONTINUE
11    CONTINUE
       RETURN
       END

Compiled to get the object file: mat_mult.o

Generate a dll: gfortran -shared -o mat_mult.dll mat_mult.o

>	fmat_mult:=define_external( 'mat_mult', LIB= "C:/Users/familee/OneDrive/Documents/Maple/DLL-example/mat_mult.dll", FORTRAN, 'a'::(ARRAY(datatype=float[8])), 'b'::(ARRAY(datatype=float[8])), 'c'::(ARRAY(datatype=float[8])), 'm'::(integer[4]), 'n'::(integer[4]), RETURN::(ARRAY(datatype=float[8])) )

(10)

The results should be the Matrix c

>	fmat_mult(a,b,c,3,3)

Error, (in fmat_mult) unhandled return type

>

mult-Fortran_dll.mw

How can I get the Compiler to work?...

Asked: Gillee 232 Product: Maple 2023

July 09 2023

1 6

I made the upgrade to Maple 2023 today and for fun I compiled a simple procedure. I got an error in Maple 2023. So I ran the same lines of code in Maple 2022 and eveything works. Does anyone sees this problem?

Download compile_ex.mw

How to convert a netlist to a ladder sch...

Asked: Gillee 232 Product: Maple 2021

November 27 2021

1 1

Hi Everyone,

I would like to convert a netlist to a ladder schematic by using Draw (Syrup). So far I have tried combinations of &+ and &// and have not achieved the correct result. Please help.

capnet:= "
V 1 0 1
L 1 2 1
C1 2 3 2uF
C2 2 4 3uF
C3 4 3 1uF
C4 4 5 1.5uF
C5 3 5 2.5uF
C6 3 0 3.5uF
C7 5 0 0.5uF
.end":

ckt:= [ V(1), L(1), C1(2.8E-6),
C2(3.E-6), C3(1.E-6),
C4(1.5E-6), C5(2.5E-6) &+ C6(3.5E-6)
]:
Draw(ckt);

Thanks.

SyrupQuestion.mw

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