Differences

This shows you the differences between two versions of the page.

--- public:calculator:guides:dm41x_curve_fitting [31/07/24 15:07 BST] – created john
+++ public:calculator:guides:dm41x_curve_fitting [06/03/25 06:49 GMT] (current) – external edit 127.0.0.1
@@ Line 2: / Line 2: @@
-====== DM41x Curve Fitting ======
+====== DM41X Curve Fitting ======
@@ Line 10: / Line 10: @@
 <key>XEQ</key><key>ALPHA</key><key>'C'</key><key>F</key><key>I</key><key>T</key><key>ALPHA</key>
+  * Save ''CFIT'' to a ''CST'' menu entry to make it easier to access
   * Clear Statistics Registers with <key>'C'</key> (''CLΣ'')
-  * Enter Statistics in usual way with ''Y'', ''ENTER'', ''X'', ''Σ+''
+  * Enter Statistics in usual way with ''Y'', <key>'ENTER'</key>, ''X'', <key>'A'</key>(''Σ+'')
+  * Don't use any data points ≤0
   * When all data pairs are entered press <key>'E'</key> (''FIT'')
+  * Now choose which type of fit to use
+    * ''L'' = Linear
+    * ''LOG'' = Logarithmic
+    * ''Ex'' = Exponential
+    * ''P'' = Power
+    * ''B'' = Best Fit
+  * <key>R/S</key> to cycle through the coefficients of the curve fit ''a'', ''b'', ''R^2'' (error ratio)
+  * You can next enter an ''x'' value to find the curve-fitted ''y'' value
+  * pressing <key>R/S</key> can exit back to the Curves menu ''L LOG Ex P B'' to try a different fit to the same data
+  * pressing <key>R/S</key> can exit back to the main menu to clear and enter a new set of data
+=== Curve Fit values ===
+  * Linear ''y = a + bx''
+  * Ex ''y = ae<sup>bx</sup>''
+  * Log ''y = a + b ln(x)''
+  * Power ''y = a x<sup>b</sup>''
+=== Example of a Best Fit (LOG) ===
+| X |0.72|1.31|1.95|2.58|3.14|
+| Y |2.16|1.61|1.16|0.85|0.5|
+  * ''CFIT''
+  * ''CLΣ''
+  * ''2.16'' <key>ENTER</key> ''0.72'' <key>'A'</key> (''Σ+'')
+  * ''1.61'' <key>ENTER</key> ''1.31'' <key>'A'</key> (''Σ+'')
+  * ''1.16'' <key>ENTER</key> ''1.95'' <key>'A'</key> (''Σ+'')
+  * ''0.85'' <key>ENTER</key> ''2.58'' <key>'A'</key> (''Σ+'')
+  * ''0.5'' <key>ENTER</key> ''3.14'' <key>'A'</key> (''Σ+'')
+  * <key>'E'</key> (''FIT'')
+  * <key>'E'</key> (''B'') //best fit//
+  * display : ''LOG''
+  * <key>R/S</key>
+  * display : ''a = 1.8515''
+  * <key>R/S</key>
+  * display : ''b = -1.1021''
+  * <key>R/S</key>
+  * display : ''r^2 = 0.9893''
+  * <key>R/S</key>
+  * display : ''X=?''
+    * enter an X value if wanted, to get a ''y''
+    * ''1.5'' <key>R/S</key>
+    * display : ''Y=1.4046''
+    * <key>R/S</key>
+    * enter another, or press <key>R/S</key> again to exit to the curve fitting menu
+  * try a different curve fit.... (''L'', ''Ex'' etc) or
+  * <key>R/S</key> to exit to the top menu
+the curve found is '' y = 1.8515 - 1.1021 ln(x)''
 --- //John Pumford-Green 31/07/24 14:46 BST//
@@ Line 22: / Line 76: @@
-{{tag>}}
+{{tag>calculator dm41x}}