MATLAB: Normalizing the E descriptor

f90formatformat descriptorsfortrannormalized

I've created data files with Matlab using the E descriptor for the number format. This produces output of the form:
-1.0345359317572725e-002
1.0802940928336107e+000
However, a Fortran90 based code in which I need to load the data can't interpret this format. It expects to see numbers that are "Normalized," that is, the number is shifted over so that the first digit is in the tenths position. A leading zero and decimal are always present and a minus sign, if needed. For example, our above numbers need to be in the form:
-0.10345359317572725e-001
0.10802940928336107e+001
I've been trying to get the data into this format and have managed to do so in a script by converting the numbers to strings, doing the logic, and returning a cell of strings. However I am unable to write this data to a file without losing my format. Is there a simpler way to normalize the number format? Is there a way to write a cell array of strings to a regular file?
Source for Fortran Format Descriptors

Best Answer

This does essentially what you want it to do. I didn't put it in a neat ‘function’ form because I'm not certain how you want to use it:
          x = [pi; 10*pi; 100*pi; eps; -eps; 1/eps; realmax/10; realmin];
          for k1 = 1:length(x)
              if abs(x(k1)) >= 1
                  xpnt(k1) = fix(log10(abs(x(k1))))+1;
                  x1(k1) = x(k1)./(10.^(xpnt(k1)));
              elseif abs(x(k1)) < 1
                  xpnt(k1) = fix(log10(abs(x(k1))));
                  x1(k1) = x(k1)./(10.^(xpnt(k1)));
              end
              fprintf(1,'\n%18.15fE%0+4d\n', x1(k1), xpnt(k1))
          end
You can create formatted strings for each value of x by replacing the fprintf with sprintf and making the appropriate changes.
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