@Carl Love thank you for your response. I am still amazed of what can be done with Maple. The response given by @C_R 1454 is for me closer to what I was used to doing. I appreciate your support to this forum as you help so many people.

@C_R First of all thank you for your patience! You were right in your assumptions. For clearness I have added following explantion:

and

In my original example I didn't provide all data points. I added them in your worksheet and the results gets pretty close to that of Minerr. SolveBlockQuestion-AddData.mw

I have some additional questions: Is this the most efficient way in doing this type of calculation or would it better to make H a function avoiding all ~ and potential typing errors? Thank you again for all help!

@C_R when I do this elementwise I obtain:

@C_R thank you for trying to help me out. The bold = is equal to a normal = in maple. The arrow above stands for vectorization and does an elementwise approach. So in maple it would translate as (1-~(Q/Q0). The Q0, kf, kl and Qs are above the "given" are guess values. Hopefully this makes it a bit more clear.

@acer thank you I was not aware of that.

@Carl Love thank you for the additonal explanation as it was very helpful. I would love to vote you up but do not know how I can do that. Could you explain?

@Carl Love thank you so much, that did the trick. Maple is a great program, but the syntax possibilities are huge. Thanks again for taking time to help me out.

@acer You were right I made a typo. Thanks again for your willingness to help

@acer thank you again for your swift and adequate help! The second works fine and is easily adaptable to check one column, with the first I seem to have some issues in obtaining the desired result. Anyway, I can proceed.

@acer thank you for your help. That was indeed what I had in mind. Do you have a solution for my second question: how to count all numeric values in the cvs file without the cells filled with "". numelems is apparently not capable in doing this. 

@acer it refused indeed to upload the cvs file. I have zipped and attached. Looking forward for your comments.LVAD_HTX_VBLACT.zip  

@acer thank you for helping me out! I certainly will have an in depth look to the help pages you mentioned. Have a nice weekend

@acer thank you for your explanation. May I just ask you one more question? Can I use the date + time to sort an array or a vector? Thank you for your time and willingness to help me out.

@acer , thank you so much for your swift reply. It seems to work for a single input but fails for multiple input (see attached file). In your example you extract each component (year, month, ..), but is it possible to have them connected so that I can sort my vector?

Thank you

Download StringToDateTime.m

@acer thank you for your swift reply and helpful comments. I think I understand now. I apologize for these sometimes very basic questions but changing from software after 25 years seems to be more difficult for me than originally anticipated.

Best regards.