Merge lecture 6.

lecture_05/lecture_05.md

@@ -1,4 +1,193 @@
 
+
+```octave
+%plot --format svg
+```
+
+## Questions from last class
+
+When you execute the given function 
+
+my_function.m:
+
+```matlab
+function [x,y] = my_function(max_time)
+    N=100;
+    t=linspace(0,max_time,N);
+    x=t.^2;
+    y=2*t;
+end
+```
+
+as 
+
+```>> [x,y] = my_function(20);```
+
+What variables are saved to your workspace?
+
+![responses](q1.png)
+
+How do you write a help description for a function?
+
+![responses to question 2](q2.png)
+
+
+How to keep our forked ME3255S page up to date with the original
+pretty tired this morning
+
+How do I use the Github Desktop?
+
+whats your favorite football team?
+
+Will UConn's github get updated to the newest version of github?
+As u said in class trail and error is the best way of learning.
+
+I believe the % is the same as matlab where it de-links your code into text
+
+Does the @ symbol designate a pointer? 
+
+Given the change of air pressure as altitude increases, how fast would a frisbee have to travel (and spin) to hit an airplane?
+
+What is a gui?
+
+
+could you go over a nested for loop example
+
+Can't seem to get this function to produce any graph and am not sure why
+
+When are these google forms due?
+
+how do I create a new function using Github on my desktop?
+
+Can you explain the first question more in class?
+
+What is the meaning of life?
+
+Should I just know how or what these topics are or will we learn them in the future?
+
+
+
+```octave
+f =@(x) x.^2
+
+
+```
+
+    f = 
+
+        @(x)x.^2
+
+
+
+```octave
+f([1:2:10])
+f(4)
+```
+
+    ans =
+
+         1     9    25    49    81
+
+
+    ans =
+
+        16
+
+
+
+```octave
+% nested for loop example
+for i = [1:6]
+    for j = [1:3]
+        fprintf('i=%i and j=%i\n',i,j)
+    end
+end
+        
+```
+
+    i=1 and j=1
+    i=1 and j=2
+    i=1 and j=3
+    i=2 and j=1
+    i=2 and j=2
+    i=2 and j=3
+    i=3 and j=1
+    i=3 and j=2
+    i=3 and j=3
+    i=4 and j=1
+    i=4 and j=2
+    i=4 and j=3
+    i=5 and j=1
+    i=5 and j=2
+    i=5 and j=3
+    i=6 and j=1
+    i=6 and j=2
+    i=6 and j=3
+
+
+# From last class 
+
+
+```octave
+help my_function
+```
+
+    Help documentation of "my_function"
+      This function computes the velocity in the x- and y-directions given
+      three vectors of position in x- and y-directions as a function of time
+      x = x-position
+      y = y-position
+      t = time
+      output
+      vx = velocity in x-direction
+      vy = velocity in y-direction
+
+
+
+```octave
+help my_caller
+```
+
+    Help documentation of "my_caller"
+      This function computes the acceleration in the x- and y-directions given
+      three vectors of position in x- and y-directions as a function of time
+      x = x-position
+      y = y-position
+      t = time
+      output
+      ax = acceleration in x-direction
+      ay = acceleration in y-direction
+
+
+
+```octave
+t=linspace(0,10,100)'; 
+x=t.^3; % vx = 3*t^2
+y=t.^2/2;  % vy = t
+[vx,vy]=my_function(x,y,t);
+[ax,ay]=my_caller(x,y,t);
+yyaxis left
+plot(t(1:10:end),ax(1:10:end),'o',t,6*t)
+ylabel('a_{x}')
+yyaxis right
+plot(t(1:10:end),ay(1:10:end),'s',t, 1*t./t)
+ylabel('a_{y}')
+xlabel('time')
+axis([0,10,0,3])
+```
+
+
+![png](lecture_05_files/lecture_05_11_0.png)
+
+
+
+```octave
+diff_match_dims(x,t)
+```
+
+    Undefined function 'diff_match_dims' for input arguments of type 'double'.
+    
+
 # Good coding habits
 ## naming folders and files
 
@@ -24,23 +213,18 @@ function i=code(j)
 end
 ```
 
+    Error: Function definitions are not permitted in this context.
+    
+
 
 ```octave
 help code
 ```
 
-    'code' is a command-line function
-
-     Example of bad variable names and bad function name
-
+    code not found.
 
-    Additional help for built-in functions and operators is
-    available in the online version of the manual.  Use the command
-    'doc <topic>' to search the manual index.
-
-    Help and information about Octave is also available on the WWW
-    at http://www.octave.org and via the help@octave.org
-    mailing list.
+    Use the Help browser search field to search the documentation, or
+    type "help help" for help command options, such as help for methods.
 
 
 ## Choose variable names that describe the variable
@@ -85,8 +269,8 @@ help counting_function
 1. Clone your homework_1 to your computer
 2. open Matlab (cli, jupyter or gui)
 3. Change working directory to homework_1 *e.g.* Windows:`cd('C:\Users\rcc02007\Documents\Github\homework_1')`, Mac: `cd('/Users/rcc02007/Documents/Github/homework_1')`
-4. You have already created your first script `myscript.m` (if not see lecture_4)
-5. Run `>> my_script.m`
+4. You have already created your first script `setdefaults.m` (if not see lecture_4)
+5. Run `>> setdefaults.m`
 6. Create a new m-file called nitrogen_pressure.m
 7. Create a function based upon the ideal gas law for nitrogen, Pv=RT
     1. R=0.2968 kJ/(kg-K)
@@ -96,14 +280,45 @@ help counting_function
 9. After file is 'committed', 'push' the changes to your github account
 
 for the command-line git user, this is steps 8 and 9:
-
 1. `$ git add *`
 2. `$ git commit -m 'added file nitrogen_pressure.m'`
 3. `$ git push -u origin master
     Username for 'https://github.uconn.edu':rcc02007 <enter>
-    `
+    Password for 'https://rcc02007@github.uconn.edu': `
 
 
+Now, use this function to plot the range of pressures that a pressure vessel would experience if it is 1000 gallons (3.79 m^3) with 10-20 kg of Nitrogen and temperatures range from -10 to 35 degrees C. 
+
+```matlab
+v=0.379/linspace(50,20,10);
+T=273.15+linspace(-10,35,10);
+[v_grid,T_grid]=meshgrid(v,T);
+P = nitrogen_pressure(v,T);
+pcolor(v_grid,T_grid,P)
+```
+
+
+```octave
+setdefaults;
+v=3.79./linspace(10,20,10);
+T=273.15+linspace(-10,35,10);
+[v_grid,T_grid]=meshgrid(v,T);
+P = nitrogen_pressure(v_grid,T_grid);
+pcolor(v_grid,T_grid-273.15,P-100)
+xlabel('specific volume (m^3/kg)')
+ylabel('Temperature (C)')
+%zlabel('Pressure (kPa)')
+
+%colormap winter
+%colormap summer
+%colormap jet
+colorbar()
+```
+
+
+![png](lecture_05_files/lecture_05_25_0.png)
+
+
 
 ```octave
 

lecture_05/my_caller.m

@@ -0,0 +1,23 @@
+function [ax,ay]=my_caller(x,y,t)
+    % Help documentation of "my_caller"
+    % This function computes the acceleration in the x- and y-directions given
+    % three vectors of position in x- and y-directions as a function of time
+    % x = x-position
+    % y = y-position
+    % t = time
+    % output
+    % ax = acceleration in x-direction
+    % ay = acceleration in y-direction
+
+    function v=diff_match_dims(x,t)
+      v=zeros(length(t),1);
+      v(1:end-1)=diff(x)./diff(t);
+      v(end)=v(end-1);
+    end
+
+    [vx,vy]=my_function(x,y,t);
+
+    ax = diff_match_dims(vx,t);
+    ay = diff_match_dims(vy,t);
+
+end

lecture_05/my_function.m

@@ -0,0 +1,21 @@
+function [vx,vy] = my_function(x,y,t)
+    % Help documentation of "my_function"
+    % This function computes the velocity in the x- and y-directions given
+    % three vectors of position in x- and y-directions as a function of time
+    % x = x-position
+    % y = y-position
+    % t = time
+    % output
+    % vx = velocity in x-direction
+    % vy = velocity in y-direction
+
+    vx=zeros(length(t),1);
+    vy=zeros(length(t),1);
+
+    vx(1:end-1) = diff(x)./diff(t); % calculate vx as delta x/delta t
+    vy(1:end-1) = diff(y)./diff(t); % calculate vy as delta y/delta t
+
+    vx(end) = vx(end-1);
+    vy(end) = vy(end-1);
+
+end

lecture_05/nitrogen_pressure.m

@@ -0,0 +1,10 @@
+function P=nitrogen_pressure(v,T)
+  % function to calculate Pressure of Nitrogen using ideal gas law given the specific
+  % volume, v (m^3/kg), and temperature, T (K)
+  % Pv = RT
+  %  R=0.2968; % kJ/kg-K
+  % P [in kPa] = nitrogen_pressure(v [in m^3/kg], T[in K])
+  R=0.2968; % kJ/kg-K
+  P=R*T./v;
+end
+

lecture_05/setdefaults.m

@@ -0,0 +1,3 @@
+set(0, 'defaultAxesFontSize', 16)
+set(0,'defaultTextFontSize',14)
+set(0,'defaultLineLineWidth',3)