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Usage
FreeMat supports several modes for displaying matrices
(either through the 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.
Example
We start with the short format, and two matrices, one of
double precision, and the other of single precision.
--> format short
--> a = randn(4)
a =
-0.3756 0.0920 0.9516 1.8527
0.5078 -0.2088 -0.3120 -0.2380
0.5578 0.7695 0.0226 2.9326
-0.4420 -0.4871 -0.7582 -0.5059
--> b = float(randn(4))
b =
0.2010 0.3416 0.1562 -0.5460
1.2842 -0.3808 -1.2720 -0.3398
-0.7660 -0.6251 2.4811 0.7956
-0.1727 0.8577 1.5701 -1.5048
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 =
Columns 1 to 3
-0.37559630424227 0.09196341864118 0.95155934364300
0.50776589164635 -0.20877480315311 -0.31198760445638
0.55783547335483 0.76954243414671 0.02264031516947
-0.44202929771190 -0.48708606879623 -0.75822963661106
Columns 4 to 4
1.85265231634028
-0.23799081322695
2.93263318869123
-0.50590405332950
--> b
ans =
0.2010476 0.3415550 0.1561587 -0.5460028
1.2841575 -0.3808453 -1.2719837 -0.3397521
-0.7659672 -0.6251388 2.4811494 0.7956446
-0.1726678 0.8576548 1.5701485 -1.5048176
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 *
-0.3756 0.0920 0.9516 1.8527
0.5078 -0.2088 -0.3120 -0.2380
0.5578 0.7695 0.0226 2.9326
-0.4420 -0.4871 -0.7582 -0.5059
--> a*1e-4
ans =
1.0e-04 *
-0.3756 0.0920 0.9516 1.8527
0.5078 -0.2088 -0.3120 -0.2380
0.5578 0.7695 0.0226 2.9326
-0.4420 -0.4871 -0.7582 -0.5059
--> b*1e4
ans =
1.0e+04 *
0.2010 0.3416 0.1562 -0.5460
1.2842 -0.3808 -1.2720 -0.3398
-0.7660 -0.6251 2.4811 0.7956
-0.1727 0.8577 1.5701 -1.5048
--> b*1e-4
ans =
1.0e-04 *
0.2010 0.3416 0.1562 -0.5460
1.2842 -0.3808 -1.2720 -0.3398
-0.7660 -0.6251 2.4811 0.7956
-0.1727 0.8577 1.5701 -1.5048
Next, we use the exponential formats:
--> format short e
--> a*1e4
ans =
-3.7560e+03 9.1963e+02 9.5156e+03 1.8527e+04
5.0777e+03 -2.0877e+03 -3.1199e+03 -2.3799e+03
5.5784e+03 7.6954e+03 2.2640e+02 2.9326e+04
-4.4203e+03 -4.8709e+03 -7.5823e+03 -5.0590e+03
--> a*1e-4
ans =
-3.7560e-05 9.1963e-06 9.5156e-05 1.8527e-04
5.0777e-05 -2.0877e-05 -3.1199e-05 -2.3799e-05
5.5784e-05 7.6954e-05 2.2640e-06 2.9326e-04
-4.4203e-05 -4.8709e-05 -7.5823e-05 -5.0590e-05
--> b*1e4
ans =
2.0105e+03 3.4156e+03 1.5616e+03 -5.4600e+03
1.2842e+04 -3.8085e+03 -1.2720e+04 -3.3975e+03
-7.6597e+03 -6.2514e+03 2.4811e+04 7.9564e+03
-1.7267e+03 8.5765e+03 1.5701e+04 -1.5048e+04
--> b*1e-4
ans =
2.0105e-05 3.4155e-05 1.5616e-05 -5.4600e-05
1.2842e-04 -3.8085e-05 -1.2720e-04 -3.3975e-05
-7.6597e-05 -6.2514e-05 2.4811e-04 7.9564e-05
-1.7267e-05 8.5765e-05 1.5701e-04 -1.5048e-04
Finally, if we assign the format function to a variable, we
can retrieve the current format:
--> format short
--> t = format
t =
short
* FreeMat_Documentation
* Input/Ouput_Functions
* Generated on Thu Jul 25 2013 17:17:38 for FreeMat by
doxygen_ 1.8.1.1
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