×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Paramatising a solve block with multiple unit types

Paramatising a solve block with multiple unit types

(OP)
Hi there,

I have set of equations that I need to solve numerically (colebrook-white, darcy, and bernouli equations). I express these equations in a solve block and use find to solve. Explicit matrix form works fine:
{x, y, z} = find(x,y,z)

However, I want to paramatise this solve block i.e:

f(x,y,z) = find(x,y,z)

but, x,y, and z, have the dimensions (m/s), (1) and (m) and mathcad doesnt support matricies of differing types as mentioned in the help page for find.

Mathcad must have a good reason for maintaining data in homogeneous matricies but I guess there must be a way to do what I need.

Any ideas how to achieve this?

I tried getting just one variable from the solve block, since this can be used to identify the state of all others but mathcad needs all three variables specified in the find function in order to solve (not sure why this is).

RE: Paramatising a solve block with multiple unit types

No, Mathsoft didn't have a particularly good reason to restrict arrays to single data type. From Mathcad 12 onwards it was disallowed because the newly introduced static data type checking couldn't guarantee the result type if mixed units were allowed. Allowing mixed data types (and a return to allowing functions and values to be mixed in an array, as in Mathcad 11) was a long-standing feature request from many users. For some reason, Mathsoft and, subsequently, PTC stubbornly refused to do anything about it. However, I believe PTC have lifted the restriction in Mathcad Prime.

As for getting round it, I'm afraid the only method I know of is to remove units from the variables and add them back afterwards (look up the SIUnitsOf function).

RE: Paramatising a solve block with multiple unit types

(OP)
Thanks,

This approach occurred to me but I like my units and thought I was missing something fundamental!

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a partâ€™s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!