Section: Input/Ouput Functions
disp function or simply by entering expressions on the command line.
There are several options for the format command. The default mode is equivalent
to
format short
which generally displays matrices with 4 decimals, and scales matrices if the entries
have magnitudes larger than roughly 1e2 or smaller than 1e-2. For more
information you can use
format long
which displays roughly 7 decimals for float and complex arrays, and 14 decimals
for double and dcomplex. You can also use
format short e
to get exponential format with 4 decimals. Matrices are not scaled for exponential formats. Similarly, you can use
format long e
which displays the same decimals as format long, but in exponential format.
You can also use the format command to retrieve the current format:
s = format
where s is a string describing the current format.
--> format short
--> a = randn(4)
a =
-0.3610 0.1437 -0.6212 -0.8556
-0.5851 -0.6293 -0.7944 0.7246
-0.7003 3.0445 -0.2511 -0.3654
-1.5856 0.4217 0.9614 0.5157
--> b = float(randn(4))
b =
-0.6938 -1.7681 0.2468 0.9813
0.3994 1.1454 -0.9926 0.2513
-0.4021 -0.7800 0.3820 -1.3138
-0.1383 -1.4973 -0.3438 0.9952
Note that in the short format, these two matrices are displayed with the same format.
In long format, however, they display differently
--> format long --> a ans = -0.36104109917203 0.14371748458334 -0.62119867856148 -0.85561084566703 -0.58514130479808 -0.62934886335610 -0.79443760799311 0.72456209775698 -0.70030658677887 3.04451182288483 -0.25112914812979 -0.36541385410128 -1.58558937953551 0.42165459944770 0.96139968715180 0.51566533614799 --> b ans = -0.6937948 -1.7681128 0.2468418 0.9813337 0.3994139 1.1454117 -0.9926057 0.2513486 -0.4021498 -0.7800179 0.3820494 -1.3138303 -0.1382517 -1.4973482 -0.3438159 0.9952367
Note also that we we scale the contents of the matrices, FreeMat rescales the entries with a scale premultiplier.
--> format short
--> a*1e4
ans =
1.0e+04 *
-0.3610 0.1437 -0.6212 -0.8556
-0.5851 -0.6293 -0.7944 0.7246
-0.7003 3.0445 -0.2511 -0.3654
-1.5856 0.4217 0.9614 0.5157
--> a*1e-4
ans =
1.0e-04 *
-0.3610 0.1437 -0.6212 -0.8556
-0.5851 -0.6293 -0.7944 0.7246
-0.7003 3.0445 -0.2511 -0.3654
-1.5856 0.4217 0.9614 0.5157
--> b*1e4
ans =
1.0e+04 *
-0.6938 -1.7681 0.2468 0.9813
0.3994 1.1454 -0.9926 0.2513
-0.4021 -0.7800 0.3820 -1.3138
-0.1383 -1.4973 -0.3438 0.9952
--> b*1e-4
ans =
1.0e-04 *
-0.6938 -1.7681 0.2468 0.9813
0.3994 1.1454 -0.9926 0.2513
-0.4021 -0.7800 0.3820 -1.3138
-0.1383 -1.4973 -0.3438 0.9952
Next, we use the exponential formats:
--> format short e --> a*1e4 ans = -3.6104e+03 1.4372e+03 -6.2120e+03 -8.5561e+03 -5.8514e+03 -6.2935e+03 -7.9444e+03 7.2456e+03 -7.0031e+03 3.0445e+04 -2.5113e+03 -3.6541e+03 -1.5856e+04 4.2165e+03 9.6140e+03 5.1567e+03 --> a*1e-4 ans = -3.6104e-05 1.4372e-05 -6.2120e-05 -8.5561e-05 -5.8514e-05 -6.2935e-05 -7.9444e-05 7.2456e-05 -7.0031e-05 3.0445e-04 -2.5113e-05 -3.6541e-05 -1.5856e-04 4.2165e-05 9.6140e-05 5.1567e-05 --> b*1e4 ans = -6.9379e+03 -1.7681e+04 2.4684e+03 9.8133e+03 3.9941e+03 1.1454e+04 -9.9261e+03 2.5135e+03 -4.0215e+03 -7.8002e+03 3.8205e+03 -1.3138e+04 -1.3825e+03 -1.4973e+04 -3.4382e+03 9.9524e+03 --> b*1e-4 ans = -6.9379e-05 -1.7681e-04 2.4684e-05 9.8133e-05 3.9941e-05 1.1454e-04 -9.9261e-05 2.5135e-05 -4.0215e-05 -7.8002e-05 3.8205e-05 -1.3138e-04 -1.3825e-05 -1.4973e-04 -3.4382e-05 9.9524e-05
Finally, if we assign the format function to a variable, we can retrieve the
current format:
--> format short --> t = format t = short