Find Attribute Array Statistics¶
DREAM3D Review (Statistics)
This Filter computes a variety of statistics for a given scalar array. The currently available statistics are array length, minimum, maximum, (arithmetic) mean, median, standard deviation, and summation; any combination of these statistics may be computed by this Filter. Any scalar array, of any primitive type, may be used as input. The type of the output arrays depends on the kind of statistic computed:
|Length||signed 64-bit integer|
|Minimum||same type as input|
|Maximum||same type as input|
The user may optionally use a mask to specify points to be ignored when computing the statistics; only points where the supplied mask is true will be considered when computing statistics. Additionally, the user may select to have the statistics computed per Feature or Ensemble by supplying an Ids array. For example, if the user opts to compute statistics per Feature and selects an array that has 10 unique Feature Ids, then this Filter will compute 10 sets of statistics (e.g., find the mean of the supplied array for each Feature, find the total number of points in each Feature (the length), etc.).
The input array may also be standardized, meaning that the array values will be adjusted such that they have a mean of 0 and unit variance. This Standardize Data option requires the selection of both the Find Mean and Find Standard Deviation options. The standardized data will be saved as a new array object stored in the same Attribute Matrix as the input array. Note that if the Standardize Data option is selected, the mean and standard deviation values created by this Filter reflect the mean and standard deviation of the original array; the new standardized array has a mean of 0 and unit variance. The standardized array will be computed in double precision. If the statistics are being computed per Feature or Ensemble, then the array values are standardized according to the mean and standard deviation for each Feature/Ensemble. For example, if 5 unique Features were being analyzed and Standardize Data was selected, then the array values for Feature 1 would be standardized according to the mean and standard deviation for Feature 1, then the array values for Feature 2 would be standardized according to the mean and standard deviation for Feature 2, and so on for the remaining Features.
The user must select a destination Attribute Matrix in which the computed statistics will be stored. If electing to Compute Statistics Per Feature/Ensemble, then a reasonable selection for this array is the Feature/Ensemble Attribute Matrix associated with the supplied Feature/Ensemble Ids. However, the only requirement is that the number of columns in the selected destination Attribute Matrix match the number of Features/Ensembles specified by the supplied Id array. This requirement is enforced at run time. If computing statistics for the entire input array, then only one value is computed per statistic; therefore, the arrays produced only contain one value. In this case, the destination Attribute Matrix should only contain 1 tuple. If such a Generic Attribute Matrix does not exist, it can be created.
Special operations occur for certain statistics if the supplied array is of type bool (for example, a mask array produced when thresholding). The length, minimum, maximum, median, and summation are computed as normal (although the resulting values may be platform dependent). The mean and standard deviation for a boolean array will be true if there are more instances of true in the array than false. If Standardize Data is chosen for a boolean array, no actual modifications will be made to the input. These operations for boolean inputs are chosen as a basic convention, and are not intended be representative of true boolean logic.
|Find Length||bool||Whether to compute the length of the input array|
|Find Minimum||bool||Whether to compute the minimum of the input array|
|Find Maximum||bool||Whether to compute the maximum of the input array|
|Find Mean||bool||Whether to compute the arithmetic mean of the input array|
|Find Median||bool||Whether to compute the median of the input array|
|Find Standard Deviation||bool||Whether to compute the standard deviation of the input array|
|Find Summation||bool||Whether to compute the summation of the input array|
|Use Mask||bool||Whether to use a boolean mask array to ignore certain points flagged as false from the statistics|
|Compute Statistics Per Feature/Ensemble||bool||Whether the statistics should be computed on a Feature/Ensemble basis|
|Standardize Data||bool||Whether the input array should be standardized to have mean of 0 and unit variance; Find Mean and Find Standard Deviation must be selected to use this option|
|Kind||Default Name||Type||Component Dimensions||Description|
|Any Attribute Array||None||Any||(1)||Input Attribute Array for which to compute statistics|
|Attribute Array||None||int32_t||(1)||Specifies to which Feature/Ensemble each point in the input Attribute Array belongs, if Compute Statistics Per Feature/Ensemble is checked|
|Attribute Array||Mask||bool||(1)||Specifies if the point is to be counted in the statistics, if Use Mask is checked|
|Destination Attribute Matrix||None||Any||N/A||Attribute Matrix in which to store the computed statistics|
|Kind||Default Name||Type||Component Dimensions||Description|
|Attribute Array||Length||int64_t||(1)||Length of the input array, if Find Length is checked|
|Attribute Array||Minimum||same as input Attribute Array||(1)||Minimum of the input array, if Find Minimum is checked|
|Attribute Array||Maximum||same as input Attribute Array||(1)||Maximum of the input array, if Find Maximum is checked|
|Attribute Array||Mean||double||(1)||Arithmetic mean of the input array, if Find Mean is checked|
|Attribute Array||Median||double||(1)||Median of the input array, if Find Median is checked|
|Attribute Array||Standard Deviation||double||(1)||Standard deviation of the input array, if Find Standard Deviation is checked|
|Attribute Array||Summation||double||(1)||Summation of the input array, if Find Summation is checked|
|Attribute Array||Standardized||double||(1)||Standardized version of the input array, if Standardize Data is checked|
License & Copyright¶
Please see the description file distributed with this plugin.
DREAM3D Mailing Lists¶
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