Reading cases from a file - matlab

Question

I have different cases resulting from my popupmenu. However, I would like to have a some sort of file (for example .mat) where the cases are read from (in for example a for loop?). How is this is possible to implement?
% --- Executes on selection change in hd_poweramp.
function hd_poweramp_Callback(hObject, eventdata, handles)
% hObject handle to hd_poweramp (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
val = get(hObject, 'Value');
str = get(hObject, 'String');
switch str{val}
case '325LA Precision Acoustics'
if handles.transducer_index == 1;
handles.fgen1_voltage = (handles.fgen1_PNP*2-28.8)/0.72; % Double check that
else if handles.transducer_index == 2;
handles.fgen1_voltage = (handles.fgen1_PNP*2-28.8)/6.055; % Double check that
end
end
case '2100L E&I'
if handles.transducer_index == 1;
handles.fgen1_voltage = (handles.fgen1_PNP*2-10.267)/1.6; % Double check that
else if handles.transducer_index == 2;
handles.fgen1_voltage = (handles.fgen1_PNP*2-28.8)/6.055; % Double check that
end
end
end
guidata(hObject, handles); % Update the GUI data structure

Answer 1

You can store your data in a uniform structure and use that to generate your dropdown selections and drive the calculations.
Consider the following example GUI (full code at the bottom):
Here are the 2 most relevant sections:
function makedummydata(mydatafile)
cases(1).Name = '325LA Precision Acoustics';
cases(1).ntransducers = 2;
cases(1).TransducerConstant1(1) = 28.8;
cases(1).TransducerConstant1(2) = 28.8;
cases(1).TransducerConstant2(1) = 0.72;
cases(1).TransducerConstant2(2) = 6.055;
cases(2).Name = '2100L E&I';
cases(2).ntransducers = 2;
cases(2).TransducerConstant1(1) = 10.267;
cases(2).TransducerConstant1(2) = 28.8;
cases(2).TransducerConstant2(1) = 1.6;
cases(2).TransducerConstant2(2) = 6.055;
save(mydatafile, 'cases');
end
And
function recalc(hObj, ~)
handles = guidata(hObj);
deviceID = handles.devicedd.Value;
transducerID = handles.transducerdd.Value;
fgen1_PNP = str2double(handles.fgen1_PNP.String);
TransducerConstant1 = handles.UserData(deviceID).TransducerConstant1(transducerID);
TransducerConstant2 = handles.UserData(deviceID).TransducerConstant2(transducerID);
voltage = (fgen1_PNP*2 - TransducerConstant1)/TransducerConstant2;
handles.resultsbox.String = voltage;
end
Here I've created an array of structures where each top level index corresponds to a device and its relevant constants. When the GUI is generated, the dropdown list is populated with all of the device names and the transducer list is populated with the number of transducers available for the device.
When you make changes to either one of the dropdowns or the fgen1 PNP, the voltage is recalculated. Note how simple the recalculation function is. Because we set up our data structure in a MATLAB-ic way, we can easily access all of the relevant portions without requiring loops, string manipulations, or the dreaded eval.
Full GUI code:
function testcode
% Set up sample data
mydatafile = 'mydevices.mat';
makedummydata(mydatafile);
buildGUI(mydatafile);
end
function recalc(hObj, ~)
handles = guidata(hObj);
deviceID = handles.devicedd.Value;
transducerID = handles.transducerdd.Value;
fgen1_PNP = str2double(handles.fgen1_PNP.String);
TransducerConstant1 = handles.UserData(deviceID).TransducerConstant1(transducerID);
TransducerConstant2 = handles.UserData(deviceID).TransducerConstant2(transducerID);
voltage = (fgen1_PNP*2 - TransducerConstant1)/TransducerConstant2;
handles.resultsbox.String = voltage;
end
function makedummydata(mydatafile)
cases(1).Name = '325LA Precision Acoustics';
cases(1).ntransducers = 2;
cases(1).TransducerConstant1(1) = 28.8;
cases(1).TransducerConstant1(2) = 28.8;
cases(1).TransducerConstant2(1) = 0.72;
cases(1).TransducerConstant2(2) = 6.055;
cases(2).Name = '2100L E&I';
cases(2).ntransducers = 2;
cases(2).TransducerConstant1(1) = 10.267;
cases(2).TransducerConstant1(2) = 28.8;
cases(2).TransducerConstant2(1) = 1.6;
cases(2).TransducerConstant2(2) = 6.055;
save(mydatafile, 'cases');
end
function buildGUI(mydatafile)
% Generate GUI
h.f = figure('MenuBar', 'none', 'ToolBar', 'none', 'NumberTitle', 'off');
cases = load(mydatafile, 'cases');
h.UserData = cases.cases; % Remove extra layer
h.lbl(1) = uicontrol('Parent', h.f, 'Style', 'Text', ...
'Units', 'Normalized', 'Position', [0.1 0.7 0.6 0.1], ...
'FontSize', 12, 'HorizontalAlignment', 'left', 'String', 'Device Thing');
h.devicedd = uicontrol('Parent', h.f, 'Style', 'popupmenu', ...
'Units', 'Normalized', 'Position', [0.1 0.55 0.6 0.2], ...
'String', {h.UserData(:).Name}, 'Callback', #recalc);
h.lbl(2) = uicontrol('Parent', h.f, 'Style', 'Text', ...
'Units', 'Normalized', 'Position', [0.1 0.5 0.6 0.1], ...
'FontSize', 12, 'HorizontalAlignment', 'left', 'String', 'Transducer Thing');
h.transducerdd = uicontrol('Parent', h.f, 'Style', 'popupmenu', ...
'Units', 'Normalized', 'Position', [0.1 0.35 0.6 0.2], ...
'String', 1:h.UserData(1).ntransducers, 'Callback', #recalc);
h.lbl(3) = uicontrol('Parent', h.f, 'Style', 'Text', ...
'Units', 'Normalized', 'Position', [0.1 0.3 0.3 0.1], ...
'FontSize', 12, 'HorizontalAlignment', 'left', 'String', 'fgen1 PNP Thing');
h.fgen1_PNP = uicontrol('Parent', h.f, 'Style', 'edit', ...
'Units', 'Normalized', 'Position', [0.1 0.25 0.25 0.1], ...
'String', 1);
h.lbl(4) = uicontrol('Parent', h.f, 'Style', 'Text', ...
'Units', 'Normalized', 'Position', [0.5 0.3 0.3 0.1], ...
'FontSize', 12, 'HorizontalAlignment', 'left', 'String', 'Result');
h.resultsbox = uicontrol('Parent', h.f, 'Style', 'edit', ...
'Units', 'Normalized', 'Position', [0.5 0.25 0.25 0.1]);
guidata(h.f, h);
recalc(h.f, 'hi'); % Fire first calc
end