DAP4: Subsetting Arrays and Grids By Value - Revision history

Ndp: /* Proposed solution */

2012-04-30T18:09:03Z

Proposed solution

← Older revision		Revision as of 18:09, 30 April 2012
Line 60:		Line 60:
	</source></font>		</source></font>

	And the evaluation might look something like this (pseudo-code):		And the evaluation might look something like this (pseudo-code) for a returned sequence:

	<font size="2"><source lang="java">		<font size="2"><source lang="java">


	for(int x=0; x<1024 ; x++){		for(int x=0; x<1024 ; x++){
	for(int y=0; y<1024 ; y++){		for(int y=0; y<1024 ; y++){
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	match_lon = lon[x][y];		match_lon = lon[x][y];
	match_depth = depth[x][y][z];		match_depth = depth[x][y][z];
	~~send_row~~(match_sal, match_lat, match_lon, match_depth);		send_sequence_row(match_sal, match_lat, match_lon, match_depth);
			}
			}
			}
			}
			</source></font>

			Or the evaluation might look something like this (pseudo-code) for a returned mask:

			<font size="2"><source lang="java">

			int xsize = 1024;
			int ysize = 1024;
			int zsize = 1000;

			Mask sal_mask = new Mask(x,y,z);
			sal_mask.setAll(false);

			for(int x=0; x<1024 ; x++){
			for(int y=0; y<1024 ; y++){
			for(int z=0; z<1000 ; z++){
			if(sal[x][y][z] < 3.2){
			match_sal = sal[x][y][z];
			sal_mask.set(x,y,z,true);
	}		}
	}		}
	}		}
	}		}

			sal_mask.serialize();

	</source></font>		</source></font>

Ndp: /* Proposed solution */

2012-04-30T15:19:24Z

Proposed solution

← Older revision		Revision as of 15:19, 30 April 2012
Line 19:		Line 19:
	<Dimension name="x" size="1024"/>		<Dimension name="x" size="1024"/>
	<Dimension name="y" size="1024"/>		<Dimension name="y" size="1024"/>
	<Dimension name="z" size="12"/>		<Dimension name="z" size="1000"/>

	<!-- The dimensions of a Coordinate MUST be SharedDimensions -->		<!-- The dimensions of a Coordinate MUST be SharedDimensions -->
	<~~Map~~ name="lon~~" type="Float32~~">		<Float32 name="lon">
	<dimension ref="x"/>		<dimension ref="x"/>
	<dimension ref="y"/>		<dimension ref="y"/>
	</Map>		</Map>

	<~~Map~~ name="lat~~" type="Float32~~">		<Float32 name="lat">
	<dimension ref="x"/>		<dimension ref="x"/>
	<dimension ref="y"/>		<dimension ref="y"/>
	</Map>		</Map>

	<~~Map~~ name="depth~~" type="Float32~~">		<Float32 name="depth">
	<Attribute name="unit" type="String"><value>meters</value></Attribute>		<Attribute name="unit" type="String"><value>meters</value></Attribute>
	<dimension ref="x"/>		<dimension ref="x"/>
Line 41:		Line 41:
	<Float64 name="sal">		<Float64 name="sal">
	<dimension ref="x"/>		<dimension ref="x"/>
	<dimension ref="x"/>		<dimension ref="y"/>
	<dimension ref="z"/>		<dimension ref="z"/>
	<map name="lat" />		<map name="lat" />
Line 58:		Line 58:
	<Float32 name="depth"/>		<Float32 name="depth"/>
	</Sequence>		</Sequence>
			</source></font>

			And the evaluation might look something like this (pseudo-code):

			<font size="2"><source lang="java">


			for(int x=0; x<1024 ; x++){
			for(int y=0; y<1024 ; y++){
			for(int z=0; z<1000 ; z++){
			if(sal[x][y][z] < 3.2){
			match_sal = sal[x][y][z];
			match_lat = lat[x][y];
			match_lon = lon[x][y];
			match_depth = depth[x][y][z];
			send_row(match_sal, match_lat, match_lon, match_depth);
			}
			}
			}
			}

	</source></font>		</source></font>

DennisHeimbigner at 17:50, 29 April 2012

2012-04-29T17:50:13Z

← Older revision		Revision as of 17:50, 29 April 2012
Line 67:		Line 67:
	[[User:dmh\|Dennis]](4/28/2012) I like this proposal. It avoids the problem of using variable length dimensions and provides an additional use for sequences.		[[User:dmh\|Dennis]](4/28/2012) I like this proposal. It avoids the problem of using variable length dimensions and provides an additional use for sequences.

	[[User:dmh\|Dennis]](4/29/2012) I might suggest that the produced sequence should contain columns for the dimensions of the selected variable. Using the above example, I would suggest the new sequence should look like this.		[[User:dmh\|Dennis]](4/29/2012) I might suggest that the produced sequence should contain columns for the dimensions of the selected variable. Using the above example, I would suggest the new sequence should look like this.
			<font size="2"><source lang="xml">
			<Sequence name="sal">
			<Float64 name="sal" />
			<Int32 name="x" />
			<Int32 name="y" />
			<Int32 name="z" />
			<Float32 name="lat"/>
			<Float32 name="lon"/>
			<Float32 name="depth"/>
			</Sequence>
			</source></font>

	[[User:dmh\|Dennis]](4/28/2012) <del>I am not sure, however that I see the algorithm for choosing the values for the map columns. Nathan, can you elaborate on the rule for doing that?</del> Never mind; this issues requires some detailed discussion.		[[User:dmh\|Dennis]](4/28/2012) <del>I am not sure, however that I see the algorithm for choosing the values for the map columns. Nathan, can you elaborate on the rule for doing that?</del> Never mind; this issues requires some detailed discussion.

DennisHeimbigner: /* Discussion */

2012-04-29T17:48:08Z

Discussion

← Older revision		Revision as of 17:48, 29 April 2012
Line 65:		Line 65:

	== Discussion ==		== Discussion ==
	[[User:dmh\|Dennis]](4/28/2012) ~~More to the point,~~ I like this proposal. It avoids the problem of using variable length dimensions and provides an additional use for sequences.		[[User:dmh\|Dennis]](4/28/2012) I like this proposal. It avoids the problem of using variable length dimensions and provides an additional use for sequences.

	[[User:dmh\|Dennis]](4/29/2012)		[[User:dmh\|Dennis]](4/29/2012) I might suggest that the produced sequence should contain columns for the dimensions of the selected variable. Using the above example, I would suggest the new sequence should look like this.

	[[User:dmh\|Dennis]](4/28/2012) <del>I am not sure, however that I see the algorithm for choosing the values for the map columns. Nathan, can you elaborate on the rule for doing that?</del> Never mind; this issues requires some detailed discussion.		[[User:dmh\|Dennis]](4/28/2012) <del>I am not sure, however that I see the algorithm for choosing the values for the map columns. Nathan, can you elaborate on the rule for doing that?</del> Never mind; this issues requires some detailed discussion.

DennisHeimbigner at 17:46, 29 April 2012

2012-04-29T17:46:35Z

@@ Line 65: / Line 65: @@
 == Discussion ==
 [[User:dmh|Dennis]](4/28/2012) slightly off topic. I thought we had agreed that map variables are just declared using ordinary variable declarations. The example above is using the element keyword to define coordinate variables. E.g.
 <pre>
@@ Line 80: / Line 86: @@
 </pre>
 [[User:Ndp|ndp]] That's probably the case - I was just doing a copy-pasta from somewhere else on the wiki for the example. And I'm sure that somewhere hasn't been brought into line with our current discussion. I suspect that once we iron out an agreement on the various bits of the data model we'll need to go back and rework the wiki content to reflect our thinking.

Ndp: /* Discussion */

2012-04-28T22:35:29Z

Discussion

← Older revision		Revision as of 22:35, 28 April 2012
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	</Float32>		</Float32>
	</pre>		</pre>
			[[User:Ndp\|ndp]] That's probably the case - I was just doing a copy-pasta from somewhere else on the wiki for the example. And I'm sure that somewhere hasn't been brought into line with our current discussion. I suspect that once we iron out an agreement on the various bits of the data model we'll need to go back and rework the wiki content to reflect our thinking.


	[[User:dmh\|Dennis]](4/28/2012) More to the point, I like this proposal. It avoids the problem of using variable length dimensions and provides an additional use for sequences.		[[User:dmh\|Dennis]](4/28/2012) More to the point, I like this proposal. It avoids the problem of using variable length dimensions and provides an additional use for sequences.

DennisHeimbigner at 20:13, 28 April 2012

2012-04-28T20:13:31Z

← Older revision		Revision as of 20:13, 28 April 2012
Line 80:		Line 80:
	</pre>		</pre>

	[[User:dmh\|Dennis]](4/28/2012) More to the point, I like this proposal. It avoids the problem of using variable length dimensions and provides an additional use for sequences. I am not sure, however that I see the algorithm for choosing the values for the map columns. Nathan, can you elaborate on the rule for doing that?		[[User:dmh\|Dennis]](4/28/2012) More to the point, I like this proposal. It avoids the problem of using variable length dimensions and provides an additional use for sequences.

			I am not sure, however that I see the algorithm for choosing the values for the map columns. Nathan, can you elaborate on the rule for doing that?

			Also, it does lose dimensional information that might be both useful and performance enhancing. For instance, it might be useful to be able to say something like
			<pre>?sal[0:22][0:9][]<3.2</pre>
			and get something back like this:
			<font size="2"><source lang="xml">
			<Sequence name="sal">
			<Float64 name="sal">
			<Dimension size="23" />
			<Dimension size="10" />
			</Float64>
			<Float32 name="lat"/>
			<Float32 name="lon"/>
			<Float32 name="depth"/>
			</Sequence>
			</source></font>

DennisHeimbigner at 19:51, 28 April 2012

2012-04-28T19:51:44Z

← Older revision		Revision as of 19:51, 28 April 2012
Line 65:		Line 65:

	== Discussion ==		== Discussion ==
	[[User:dmh\|Dennis]](4/28/2012) I thought we had agreed that map variables are just declared using ordinary variable declarations. The example above is using the element keyword to define coordinate variables. E.g.		[[User:dmh\|Dennis]](4/28/2012) slightly off topic. I thought we had agreed that map variables are just declared using ordinary variable declarations. The example above is using the element keyword to define coordinate variables. E.g.
	<pre>		<pre>
	<Map name="lon" type="Float32">		<Map name="lon" type="Float32">
Line 79:		Line 79:
	</Float32>		</Float32>
	</pre>		</pre>

			[[User:dmh\|Dennis]](4/28/2012) More to the point, I like this proposal. It avoids the problem of using variable length dimensions and provides an additional use for sequences. I am not sure, however that I see the algorithm for choosing the values for the map columns. Nathan, can you elaborate on the rule for doing that?

DennisHeimbigner at 19:41, 28 April 2012

2012-04-28T19:41:59Z

@@ Line 67: / Line 67: @@
 [[User:dmh|Dennis]](4/28/2012) I thought we had agreed that map variables are just declared using ordinary variable declarations. The example above is using the element keyword to define coordinate variables. E.g.
 <pre>
 </pre>

DennisHeimbigner: /* Discussion */

2012-04-28T19:40:33Z

Discussion

← Older revision		Revision as of 19:40, 28 April 2012
Line 65:		Line 65:

	== Discussion ==		== Discussion ==
			[[User:dmh\|Dennis]](4/28/2012) I thought we had agreed that map variables are just declared using ordinary variable declarations. The example above is using the element keyword to define coordinate variables. E.g.
			<pre>
			</pre>