loop or other better solution for mixing?

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addy fang 2020-7-12

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评论： addy fang 2020-7-14

Hello, I am new to Matlab and want to do some mixing, and wonder if there is any better solution other than looping.

Basically, I want to mix any number of ingredients to make one solution. The percentage of the ingredients added up should equal to 100%. The percentage of each ingredient can be from 0% to 100%. I need to go through and save all the possible compositions with distinct names, and do calculations in order to find out the best composition.

Starting with two databases A and B, each with 4 columns of numerical data. I will need to produce and save all the mixed combination. For example, 10% of each column in A add 90% of the corresponding column in B, and save the result. The total percentage is 100%. This could be done with loop. x=0:0.1:1, C=x*A+(1-x)*b. This seems straightforward, if I only have two databases A and B.

If I have three databases, A, B and C, to produce D. So I need two loops?

If I have A, B, C and D, to produce E, so I need to have three loops?

If I want to mix more, do I have to create another loop again?

As the number of the databases I want to mix increase, this looping solution seems inefficient. Because everytime the numer of database changes, I need to rewrite my code again.

I was wondering if there is any better solution for this problem. So it does not need me to redo the coding even if I change the number of databases to be mixed. I hope I only need one code to run whatever number of databases that I want to mix.

Thank you very much.

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Steven Lord 2020-7-13

Are the ingredients able to be continuously measured (i.e. 1.2345 mL of water) or are they discrete (1 egg, 2 eggs, but not 1.2345 eggs)?

Do you need the values of all possible combinations or do you need to find an optimal (according to some objective) combination?

Some of the functions in Optimization Toolbox or Global Optimization Toolbox may help particularly if your measurements are continuous.

addy fang 2020-7-13

Hi Steven, yes, the ingredients can be continuously measured (i.e., 1.2345678...mL of water). Ideally, I need all the possible combinations (compositions) to perform calculations in the next step, to eventually find the best values.

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回答（1 个）

Walter Roberson 2020-7-13

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https://ww2.mathworks.cn/matlabcentral/answers/563894-loop-or-other-better-solution-for-mixing#answer_464876

在 MATLAB Online 中打开

nd = 4;                    %number of databases, adjust as needed
vec = 0 : 0.1 : 1;
[P{1:nd}] = ndgrid(vec);
total = sum(cat(nd+1, P{:}), nd+1);
match = ismembertol(total, 1);
mixtable = cell2mat(cellfun(@(C) C(match), P, 'uniform', 0));

Each column of mixtable is now a percentage of the corresponding database to use.