**svd_snowfall_test**,
a FORTRAN90 code which
calls svd_snowfall(), which
demonstrates the use of the Singular Value Decomposition (SVD)
to analyze a set of historical snowfall data,
with plots created by GNUPLOT.

The computer code and data files described and made available on this web page are distributed under the MIT license

svd_snowfall, a FORTRAN90 code which reads a file containing historical snowfall data and analyzes the data with the Singular Value Decomposition (SVD), and plots created by gnuplot().

- svd_snowfall_test.f90, a sample calling program.
- svd_snowfall_test.sh, runs all the tests.
- svd_snowfall_test.txt, the output file.

The snowfall data itself must be read into the program from a file:

- snowfall.txt, the snowfall data.

The second test function writes "command" and "data" files that can be used by gnuplot to create plots.

- singular_values_commands.txt, a command file.
- singular_values_data.txt, a data file.
- singular_values.png, the resulting plot.

The third test function writes "command" and "data" files that can be used by gnuplot to create plots.

- approx_commands.txt, a command file.
- approx_data.txt, a data file.
- approx0.png, the 2012 snowfall (red).
- approx1.png, the 2012 snowfall (red) and rank 1 approximation (blue).
- approx2.png, the 2012 snowfall (red) and rank 2 approximation (blue).
- approx3.png, the 2012 snowfall (red) and rank 3 approximation (blue).
- approx4.png, the 2012 snowfall (red) and rank 4 approximation (blue).
- approx5.png, the 2012 snowfall (red) and rank 5 approximation (blue).

The fourth test function writes "command" and "data" files that can be used by gnuplot to create plots of the first 6 U modes, which form a basis for average snowfall as a function of the month.

- umode_commands.txt, a command file.
- umode_data.txt, a data file.
- umode1.png, basis vector 1 for snowfall as a function of month.
- umode2.png, basis vector 2 for snowfall as a function of month.
- umode3.png, basis vector 3 for snowfall as a function of month.
- umode4.png, basis vector 4 for snowfall as a function of month.
- umode5.png, basis vector 5 for snowfall as a function of month.
- umode6.png, basis vector 6 for snowfall as a function of month.

The fifth test function writes "command" and "data" files that can be used by gnuplot to create plots of the first 6 V modes, which form a basis for total yearly snowfall behavior as a function of the year.

- vmode_commands.txt, a command file.
- vmode_data.txt, a data file.
- vmode1.png, basis vector 1 for total yearly snowfall as a function of year.
- vmode2.png, basis vector 2 for total yearly snowfall as a function of year.
- vmode3.png, basis vector 3 for total yearly snowfall as a function of year.
- vmode4.png, basis vector 4 for total yearly snowfall as a function of year.
- vmode5.png, basis vector 5 for total yearly snowfall as a function of year.
- umode6.png, basis vector 6 for snowfall as a function of month.