Re: strange effect of using Item[] around Control[] in Manipulate[]
- To: mathgroup at smc.vnet.net
- Subject: [mg105582] Re: strange effect of using Item[] around Control[] in Manipulate[]
- From: "Nasser M. Abbasi" <nma at 12000.org>
- Date: Thu, 10 Dec 2009 04:55:43 -0500 (EST)
- References: <hfnuvn$gc3$1@smc.vnet.net>
"Nasser M. Abbasi" <nma at 12000.org> wrote in message news:hfnuvn$gc3$1 at smc.vnet.net... > Version 7, > > I use Item to help me arrange the layout of Controls more easily. > > I noticed the following "issue". Consider the following example: > > Manipulate[Null, > Control[{{a, 5, "a"}, 1, 10, 1}], > Control[{{b, 0.5, "b"}, 0, a, 0.01}] > ] > > In the above, control variable "b" has it maximum defined by the > control variable "a". This works ok. I us the above type construct in > many placed since the maximum value of some variable depend on the > setting of another variables. > > Now, if I wrap the above Controls in Item[], then the above will no > longer get setup correctly: > > Manipulate[Null, > Item[Control[{{a, 5, "a"}, 1, 10, 1}]], > Item[Control[{{b, 0.5, "b"}, 0, a, 0.01}]] > ] > > Now when running the above, notice that the second control is not set > up, because now its maximum value "a" is no longer seen as a the other > Manipulate control variable so its value is unknown. > > Wrapping Item[] around it caused this problem. > > Is this the expected behavior of Item in this context? > fyi, I can work around this easily by using wraping b with Dynamic, as follows Manipulate[Null, Item[Control[{{a, 5, "a"}, 1, 10, 1}]], Item[Control[{{b, 0.5, "b"}, 0, Dynamic[a], 0.01}]] ] --Nasser