CMBMCS 1A 02 April 2001 NIST NFIS Reference Manual cmbmcs combines PCASYS mean/covariance data file pairs. cmbmcs <meanfile_in meanfile_in > <covfile_in covfile_in > <meanfile_out><meanfile_out_desc><covfile_out><covfile_out_desc><ascii_outfiles> Cmbmcs combines pairs of PCASYS mean vector and covariance matrix data files, to produce a mean/covariance pair that is approximately the same as would have resulted if all the vectors that were used to make the input means and covariances had been given to the meancov function in one large set. So, if the sample covariance matrix needs to be made from a large set of vectors, and several processors are available, it may be possible to save run time by, first, running several simultaneous instances of meancov, each on a subset of the vectors, and second, running cmbmcs to combine the means and covariances made by the meancov instances. (Even if only the covariance is ultimately needed, i.e. not the mean, it is necessary for the meancov instances to compute the means and for cmbmcs to use them, to compute the overall covariance.) <meanfile_in[meanfile_in...]> Input files each containing a mean vector. These files must be in PCASYS "matrix" format, each with first dimension 1 and all having the same second dimension. (Usually the output of meancov.) <covfile_in[covfile_in...]> Input files each containing a covariance matrix. These files must be in PCASYS "covariance" format. The i'th input covariance file goes with the i'th input mean file. These covariances must all have the same order, which must be the second dimension of the input mean vector files. (Usually the output of meancov.) <meanfile_out> Mean file to be written, in PCASYS "matrix" format. <meanfile_out_desc> A string to be written into the mean output files description string. This string can be of any length, but must not contain embedded newline characters. If it contains spaces, tabs, or shell metacharacters that are not to be expanded, then it should be quoted. To leave the description empty, use '' (two single quotes, i.e. single-quoted empty string). To let cmbmcs make a description (stating that this is a mean vector made by cmbmcs and listing the names of the input files), use - (hyphen). <covfile_out> Covariance file to be produced, in PCASYS "covariance" format. Its "number of vectors" field will be set to the sum of the values of that field across the input covariances. <covfile_out_desc> Description string for output covariance file or - to let cmbmcs make the description (as for output mean file description). <ascii_outfiles> If y, makes ascii output files; if n, binary. Binary is recommended, unless the output files must be portable across different byte orders or floating_point formats. From test/pcasys/execs/cmbmcs/cmbmcs.src: % cmbmcs ../meancov/fv1.men ../meancov/fv2.men ../meancov/fv1.cov ../meancov/fv2.cov fv_tst.men - fv_tst.cov - n Combines the mean/covariance files for fv1 and fv2 into a mean/covariance set of files. meancov (1A) NIST/ITL/DIV894/Image Group