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02-15-2012
03:33 AM

02-15-2012
03:33 AM

some questions of optimization with minimize function in Mathcad 15

hi，everyone，i am a chinese，and my english is not good，this is my first time to communicate with others in english，i hope you can understand what I mean.

Now，i have a lot of problems in my work.i want to fit the experimental data using the mathcad built-in function Minimize(also,i tried Minerr).the function is known，there are 56 parameters in this function,i want to find them by making the objective function to be minimized.but when i run it,it takes a long time;also,when i change the guess value from 100 to 0，the result change as well.

So,my problems are:

1,how to reduce the time(do not change TOL or CTOL)?

2,the result must be Local optimum,and how can i find global optimum?

3,the mathcad built-in function(minimize or minerr),can i see how it works,or the inside result?

Attachment is my mathcad Calculations（mathcad 15.0）

wish for your help

my email：670442830@qq.com

thanks，my friends

it is very long,incomplete.

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3 REPLIES 3

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02-15-2012
01:13 PM

02-15-2012
01:13 PM

Re: some questions of optimization with minimize function in Mathcad 15

赵亚军 wrote:

So,my problems are:

2,the result must be Local optimum,and how can i find global optimum?

3,the mathcad built-in function(minimize or minerr),can i see how it works,or the inside result?

2. You can use a genetic method:

See - http://twt.mpei.ac.ru/MAS/Worksheets/Minimum.mcd

3. You can use the tarce function:

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02-15-2012
08:43 PM

02-15-2012
08:43 PM

Re: some questions of optimization with minimize function in Mathcad 15

thanks for your help

i have tried trace function ,but it is used for tracing independent variables(x,y),if i want to trace f(x,y),how to do that? i konw a stupid way,copy the independent variables(x,y),and then calculate f(x,y),but in my worksheet,the

independent variable is a matrix{9,9},it's too complex.are there any other functions that can trace f(x,y)?

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02-16-2012
04:11 AM

02-16-2012
04:11 AM

Re: some questions of optimization with minimize function in Mathcad 15

I think it will be better to put your question not only here but on the Mathcad branch of this forum.