User defined functions and decimal places displayed

Question

I have a couple of complicated user-defined functions, one which calls the other, and I wish to control the number of decimal places displayed when I call the "mother" function. I have tried the obvious

N[mother[],n]

but no matter the choice for n I receive only 6 decimal places. But when I write a simple nested function like

f[x_] := Module[{}, x/3];
g[x_] := Module[{}, f[x]];

and then call

N[g[1], 50]

I receive the requested number of digits (so it doesn't seem to be the nesting causing the issue). Unfortunately I cannot post the actual functions I am playing with due to their size. Any ideas would be appreciated...

Answer 1

I believe this question is a combination of these:

• Annoying display truncation of numerical results
• Confused by (apparent) inconsistent precision
• A problem about function N

Specifically, for your function to work as desired most directly (and correctly) it will need to return a number or expression in arbitrary precision. This is (best) done by using arbitrary precision or exact numbers throughout the computation.

Alternately you can use NumberForm to display your output rather than N.

The result can be forced with SetAccuracy with the understanding that your results are fake. See:

• Funny behaviour when plotting a polynomial of high degree and large coefficients