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jgvinholi1-Visitor
1-Visitor
April 9, 2018
Solved

"indexed assignment to a matrix element is not permitted in a solve block mathcad"

  • April 9, 2018
  • 12 replies
  • 5762 views

Hi, I've been trying to use some solve blocks inside a program. The solve blocks return matrixes with the solutions of the equations. I'm trying to get these results inside a program, but the error "indexed assignment to a matrix element is not permitted in a solve block mathcad" keeps showing. I don't really understand what it means. I've attached the file.

 

Edit: I haven't put any solve block inside the program, but instead tried to get outputs from outside solve blocks.

Best answer by Werner_E

The reason for the error message you get is, that you have erratically used a vector index for H1_2 in the Hi-gap solve block when assigning the guess value.

After you change that for a literal index the error is gone away, but you get a new unit mismatch error when calling Hi_iron.

Can it be that you forgot a factor S3 on the left side of the third equation?

12 replies

L
LucMeekes23-Emerald IV
23-Emerald IV
April 9, 2018

You cannot (in Mathcad or Prime) put a solve block into a program, but you can make the output of a solve block a function which you can use further.

 

Success!

Luc

J
jgvinholi1-VisitorAuthor
1-Visitor
April 9, 2018

I haven't tried to put a solve block inside a program. What I'm doing is calling functions that give outputs from other solve blocks. What I'm doing is exactly what you suggested. I've expressed Myself badly, sorry.

Thanks for the response.

L
LucMeekes23-Emerald IV
23-Emerald IV
April 9, 2018

Check your labels. The 'Hf' solve block (2nd iteration) tries to find 'Hf1[1' which is labelled as a constant (green) instead of variable (black).

 

Success!

Luc

 

    W
    Werner_E25-Diamond IAnswer
    25-Diamond I
    April 9, 2018

    The reason for the error message you get is, that you have erratically used a vector index for H1_2 in the Hi-gap solve block when assigning the guess value.

    After you change that for a literal index the error is gone away, but you get a new unit mismatch error when calling Hi_iron.

    Can it be that you forgot a factor S3 on the left side of the third equation?

      J
      jgvinholi1-VisitorAuthor
      1-Visitor
      April 9, 2018

      Thank you very much. I'll take a look closely tomorrow and will post here a feedback.

      T
      terryhendicott21-Topaz II
      21-Topaz II
      April 10, 2018

      Hi,

      In the last bit of programming for "ans" you have used an iteration of "i" from 0 to 50.

      The index "i" is not used within the programming block?  Is this intentional?

      Cheers

      Terry

        W
        Werner_E25-Diamond I
        25-Diamond I
        April 10, 2018
        @terryhendicott wrote:

        Hi,

        In the last bit of programming for "ans" you have used an iteration of "i" from 0 to 50.

        The index "i" is not used within the programming block?  Is this intentional?

        Cheers

        Terry

        I guess this is just doing the iteration 50 times hoping for convergence.

         

        I think that one single solve block can replace all the others and this loop a well:

        Bild.png

          J
          jgvinholi1-VisitorAuthor
          1-Visitor
          April 10, 2018

          That's impressive! How does Mathcad gets Hf_1 to calculate Mu_f? I thought the only way I could solve this problem was through repetitions, as I had done. Does Mathcad "know" it is needed to make a iterative process and do it by itself? Thanks for the help.

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