Explained differently in Mathematica 4.0 [can't retrieve] than reading web.
In less tan two weeks we had two parent issues:
1. matrix in program, matrix of nothing.
2. from fresh: if/else, if/Otherwise.
These two are of their own, shadow in context.
Please, read more in the attached.
Same thing happened in Mathcad "can't calculate" ... Thank you so much !

Jean

Wrote

Please, read more in the attached.

Utilities Program for loop Implicit matrix.sm (30,14 KiB) scaricato 1266 volta(e).