Wrapper function that calculates the sample point matrix from the aCGH data
calcSpm(data, mirrorLocs, sigma = 1e+06, sampleDensity = 50000, maxmem = 1000, verbose=T, old=F)
The aCGH data. Can either be in DNAcopy format or as a data.frame described in the details section
List containing the chromosome start, centromere and end positions
The sample point matrix resolution
This parameter controls memory usage, set to lower value to lower memory consumption
If set to false, no progress information is displayed
If set to true the old implementation of KCsmart will be used to calculate the spm
Returns a sample point matrix object. The object has several slots of which the 'data' slot contains a list where each list item represents a chromosome. Each list item in turn contains the sample point matrix
for the gains and the losses separately and an attribute specifying the corresponding chromosome.
The sample point matrix contains the following additional slots:
totalLength: Total length of the sample point matrix
maxy and miny: Maximal and minimal score attainedThe other slots just represent the parameters used to calculate the sample point matrix.Use 'plot' to plot the sample point matrix and 'findSigLevelTrad' to find a significance threshold.
'plotScaleSpace' can be used to plot the significant regions of multiple sample point matrices (using different sigmas).
'data' can be in cghRaw (CGHbase), DNAcopy or in data.frame format. When using the latter, the data.frame must have the following two columns: 'chrom' stating the chromosome
the probe is located on, 'maploc' describing the position on the chromosome of the probe. The remainder of the data.frame will be interpreted as sample data points.
The row names of that data will be used as probe names (when available).
Important note: the data can not contain any missing values. If your data includes missing values you will need to preprocess (for example impute) it using other software solutions.
The mirror locations for Homo Sapiens and Mus Musculus are provided in the package. These can be loaded using data(hsMirrorLocs) and data(mmMirrorLocs)
respectively. The 'mirrorLocs' object is a list with vectors containing the start, centromere (optional) and end of each chromosome as the list elements. Additionally it should
contain an attribute 'chromNames' listing the chromosome names of each respective list element.
'sigma' defines the kernel width of the kernel used to convolute the data.
'sampleDensity' defines the resolution of the sample point matrix to be calculated. A sampleDensity of 50000 would correspond to a sample point every 50k base pairs.
'old' can be used if you want to reproduce data that was generated with old (pre 2.9.0) versions of KCsmart, for any new analyses we recommend this flag to be set to false
spm1mb <- calcSpm(hsSampleData, hsMirrorLocs)
spm4mb <- calcSpm(hsSampleData, hsMirrorLocs, sigma=4000000)