## 499 Reputation

11 years, 116 days

## Thanks, I will try this...

I think calculation take less time and memory if I do not generat a Matrix

I try this

## Thanks, I will try this...

I think calculation take less time and memory if I do not generat a Matrix

I try this

I will send you by email my worksheet to give me your opinion

Perhaps there are ways to do the calculation with less time and memory

I will send you by email my worksheet to give me your opinion

Perhaps there are ways to do the calculation with less time and memory

Yes, the Matrix is correct but the construction of large system with GeneratMatrix and solve it with LinearSolve take too large memory and time.

With a matrix of 1500 by 1500, the memory is about 1,5 G bytes with a PC of 2G of memory I can not continu my calculations and Maple don't stop for all a day.

I think using connection with Matlab ?

Best regards

Yes, the Matrix is correct but the construction of large system with GeneratMatrix and solve it with LinearSolve take too large memory and time.

With a matrix of 1500 by 1500, the memory is about 1,5 G bytes with a PC of 2G of memory I can not continu my calculations and Maple don't stop for all a day.

I think using connection with Matlab ?

Best regards

## the problem is not the variable of deriv...

Thank you for the answer, but the problem is not the variable of the derivative:

restart:assume(n,integer):h := piecewise(n::odd, r*n^2, r^2*n^3);

diff(h,r);   # don't work Why ?

restart:h1 := piecewise(And(n::integer, n::odd), r*n^2, r^2*n^3);

diff(h1,r); # work

Why diff does'nt work with assume and work when the condition is given inside piecewise ?

## the problem is not the variable of deriv...

Thank you for the answer, but the problem is not the variable of the derivative:

restart:assume(n,integer):h := piecewise(n::odd, r*n^2, r^2*n^3);

diff(h,r);   # don't work Why ?

restart:h1 := piecewise(And(n::integer, n::odd), r*n^2, r^2*n^3);

diff(h1,r); # work

Why diff does'nt work with assume and work when the condition is given inside piecewise ?

## I must verrify my Matrix...

I tried LinearSolve but with no answer from maple

I think, there is some problem in my Matrix.

I will verify it and try another time

## I must verrify my Matrix...

I tried LinearSolve but with no answer from maple

I think, there is some problem in my Matrix.

I will verify it and try another time

## or...

Matrix(  [ seq ( [n, n^2], n={seq(1..3,1),50,100,1000})]);

## or...

Matrix(  [ seq ( [n, n^2], n={seq(1..3,1),50,100,1000})]);

## Error, (in DynamicSystems:-AlgEquation)...

@Wang Gaoteng Execute these equations in maple:

eq := [vs(t) = ve(t-T)];

params := [];

initialconditions := [];

sys := DynamicSystems[AlgEquation](eq, inputvariable = [ve(t)], outputvariable = [vs(t)]);

Error, (in DynamicSystems:-AlgEquation) algebraic equations cannot depend on past/future values of the input/output

## Error, (in DynamicSystems:-AlgEquation)...

@Wang Gaoteng Execute these equations in maple:

eq := [vs(t) = ve(t-T)];

params := [];

initialconditions := [];

sys := DynamicSystems[AlgEquation](eq, inputvariable = [ve(t)], outputvariable = [vs(t)]);

Error, (in DynamicSystems:-AlgEquation) algebraic equations cannot depend on past/future values of the input/output

## Custom signal with delay...

DynamicSystems dont accept equation [vs(t) = ve(t-T(t))] for any input signal and delay it.

For sinusoidal delay (for example) in above, you must introduce parameters in your signal input to get exactly the same signal in eq to work (ie f=1, amplitude=1, etc...). But, you can also work only with your block signal output which you defined in equation (eq) without input signal.

To delay other signal, you can do it in the same way with giving in eq ve(t) and vs(t) in fourier series or other expressions

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