From d1f6c89be163d9399d569e01458242d8ce15e041 Mon Sep 17 00:00:00 2001
From: wukong <wukong@longaeva>
Date: Sun, 9 Sep 2018 23:48:31 -0700
Subject: added summations to quad_reg added in-progress lpf.awk (low pass
 filter), an adaptation of convolution     script (conv.awk) to use delmitied
 columns as input additional tweaking of OFMT, OFS, and conditional print
 statements

---
 lpf.awk | 125 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 125 insertions(+)
 create mode 100644 lpf.awk

(limited to 'lpf.awk')

diff --git a/lpf.awk b/lpf.awk
new file mode 100644
index 0000000..814020f
--- /dev/null
+++ b/lpf.awk
@@ -0,0 +1,125 @@
+#!/usr/bin/awk -f
+
+### lpf.awk
+# Low Pass Filter with Hardcoded FIR Window
+
+BEGIN {
+    OFS = FS
+    sign = "[+-]?"
+    decimal = "[0-9]+[.]?[0-9]*"
+    fraction = "[.][0-9]*"
+    exponent = "([Ee]" sign "[0-9]+)?"
+    number = "^" sign "(" decimal "|" fraction ")" exponent "$"
+
+    #H = ARGV[1]
+    #H = 1.0
+    #H = "1.00   1.00    1.00"   # rect
+    #H = "0.25   0.50    0.25"   # von Hann
+    H = "0.23   0.54    0.23"   # Hamming
+    window_size = split(H, H_arr, "[ ]*")
+}
+
+NR == 1 {
+    for (y=1; y<=NF; y++)
+        ($y ~ number) ? header[y] = "col" y : header[y] = $y
+}
+
+NF > 0 {
+    if (NF > nf_max)
+        nf_max = NF
+
+    input_size = window_size 
+    output_size = (input_size + window_size - 1)
+
+    ### columns
+    for (y=1; y<=nf_max; y++) {
+        if ($y == header[y])
+            printf(header[y] OFS header[y] "_lpf")
+        if ($y ~ number) {
+            count[y]++
+
+            # rotate input buffer
+            for (n=1; n<=input_size; n++) {
+                X_arr[y,n] = X_arr[y,n+1]
+            }
+            X_arr[y,input_size] = $y
+
+            Y[y] = 0
+            for (n=1; n<=window_size; n++) {
+                for (m=1; m<=input_size; m++) {
+                    if (n <= window_size) {
+                        Y[y] += H_arr[n-m+1]*X_arr[y,m]
+                        continue
+                    }
+                    if ((n > window_size) && (n <= input_size)) {
+                        Y[y] += H_arr[n-m+1]*X_arr[y,m]
+                        continue
+                    }
+                    if ((n > window_size) && (n > input_size)) {
+                        Y[y] += H_arr[n-m+1]*X_arr[y,m]
+                        continue
+                    }
+                    else {
+                        Y[y] += 0
+                        continue
+                    }
+                }
+            }
+            printf(X_arr[y,input_size] OFS Y[y])
+        }
+
+        if (y < nf_max)
+            printf(OFS)
+        else
+            printf(ORS)
+        
+    }
+
+
+
+}
+
+END {
+    ### rows
+    for (x=1; x<=window_size; x++) {
+        ### columns
+        for (y=1; y<=nf_max; y++) {
+            # rotate input buffer
+            for (n=1; n<=input_size; n++) {
+                X_arr[y,n] = X_arr[y,n+1]
+                #print X_arr[y,n]
+            }
+            #delete X_arr[y,input_size]
+            #input_size = length(X_arr)
+            #print length(X_arr)
+            
+            Y[y] = 0
+            for (n=1; n<=window_size; n++) {
+                for (m=1; m<=input_size; m++) {
+                    if (n <= window_size) {
+                        Y[y] += H_arr[n-m+1]*X_arr[y,m]
+                        continue
+                    }
+                    if ((n > window_size) && (n <= input_size)) {
+                        Y[y] += H_arr[n-m+1]*X_arr[y,m]
+                        continue
+                    }
+                    if ((n > window_size) && (n > input_size)) {
+                        Y[y] += H_arr[n-m+1]*X_arr[y,m]
+                        continue
+                    }
+                    else {
+                        Y[y] += 0
+                        continue
+                    }
+                }
+            }
+            printf(X_arr[y,input_size] OFS Y[y])
+            if (y < nf_max)
+                printf(OFS)
+            else
+                printf(ORS)
+            X_arr[input_size] = 0 
+        }
+    }
+}
-- 
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