The SIMILARITY Procedure |
This simple example illustrates how to use similarity analysis to compare two time sequences. The following statements create an example data set that contains two time sequences of differing lengths:
data test; input i y x; datalines; 1 2 3 2 4 5 3 6 3 4 7 3 5 3 3 6 8 6 7 9 3 8 3 8 9 10 . 10 11 . ; run;
The following statements perform similarity analysis on the example data set:
ods graphics on; proc similarity data=test out=_null_ print=all plot=all; input x; target y / measure=absdev; run;
The DATA=TEST option specifies that the input data set WORK.TEST is to be used in the analysis. The OUT=_NULL_ option specifies that no output time series data set is to be created. The PRINT=ALL and PLOTS=ALL options specify that all ODS tables and graphs are to be produced. The INPUT statement specifies that the input variable is X. The TARGET statement specifies that the target variable is Y and that the similarity measure is computed using absolute deviation (MEASURE=ABSDEV).
Time Series Descriptive Statistics | |
---|---|
Variable | x |
Number of Observations | 10 |
Number of Missing Observations | 2 |
Minimum | 3 |
Maximum | 8 |
Mean | 4.25 |
Standard Deviation | 1.908627 |
Path Statistics | ||||||||
---|---|---|---|---|---|---|---|---|
Path | Number | Path Percent | Input Percent | Target Percent | Maximum | Path Maximum Percent |
Input Maximum Percent |
Target Maximum Percent |
Missing Map | 0 | 0.000% | 0.000% | 0.000% | 0 | 0.000% | 0.000% | 0.000% |
Direct Maps | 6 | 50.00% | 75.00% | 60.00% | 2 | 16.67% | 25.00% | 20.00% |
Compression | 4 | 33.33% | 50.00% | 40.00% | 1 | 8.333% | 12.50% | 10.00% |
Expansion | 2 | 16.67% | 25.00% | 20.00% | 2 | 16.67% | 25.00% | 20.00% |
Warps | 6 | 50.00% | 75.00% | 60.00% | 2 | 16.67% | 25.00% | 20.00% |
Cost Statistics | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|
Cost | Number | Total | Average | Standard Deviation | Minimum | Maximum | Input Mean | Target Mean | Minimum Path Mean | Maximum Path Mean |
Absolute | 12 | 15.00000 | 1.250000 | 1.138180 | 0 | 3.000000 | 1.875000 | 1.500000 | 1.875000 | 0.8823529 |
Relative | 12 | 2.25844 | 0.188203 | 0.160922 | 0 | 0.500000 | 0.282305 | 0.225844 | 0.282305 | 0.1328495 |
The following statements repeat the preceding similarity analysis on the example data set with warping limits:
ods graphics on; proc similarity data=test out=_null_ print=all plot=all; input x; target y / measure=absdev compress=(localabs=2) expand=(localabs=2); run;
The COMPRESS=(LOCALABS=2) option limits local absolute compression to 2. The EXPAND=(LOCALABS=2) option limits local absolute expansion to 2.
The following statements repeat the preceding similarity analysis on the example data set but store the results in output data sets:
proc similarity data=test out=series outsequence=sequences outpath=path outsum=summary; input x; target y / measure=absdev compress=(localabs=2) expand=(localabs=2); run;
The OUT=SERIES, OUTSEQUENCE=SEQUENCES, OUTPATH=PATH, and OUTSUM=SUMMARY options specify that the output time series, time sequences, path analysis, and summary data sets be created, respectively.
Note: This procedure is experimental.
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